JP6635727B2 - Optical adhesive sheet - Google Patents

Description

  The present invention relates to an optical pressure-sensitive adhesive sheet. More specifically, the present invention relates to an optical pressure-sensitive adhesive sheet for a silver nanowire layer.

  In recent years, display devices such as a liquid crystal display (LCD) and input devices such as a touch panel used in combination with such a display device have been widely used in various fields. In these display devices, input devices, and the like, an adhesive sheet having an adhesive layer is used for bonding optical members. For example, a transparent adhesive sheet is used for bonding a touch panel to various display members and optical members (for example, see Patent Documents 1 to 3).

  Some optical members used in the display device, the input device, and the like may be deteriorated by ultraviolet rays. For this reason, the pressure-sensitive adhesive sheet may be required to have ultraviolet absorbing properties (ultraviolet ray cutting property, UV cutting property). As such a pressure-sensitive adhesive sheet, a transparent pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer contains an ultraviolet absorber (see Patent Document 4) has been proposed.

  Above all, in applications such as production of a capacitive touch panel, a metal thin film such as an ITO (indium tin oxide) film or a metal oxide thin film (hereinafter, a metal thin film and a metal oxide thin film are collectively referred to as a “metal thin film”) In some cases), and may be used by directly attaching an adhesive sheet. In such applications, the pressure-sensitive adhesive sheet is further required to have a so-called corrosion resistance that does not corrode the metal thin film.

  However, when an adhesive sheet made of an acrylic polymer or the like in which a carboxyl group-containing monomer is used as a monomer component is used as an adhesive sheet to be attached to a metal thin film as described above, when stored under humidified conditions, There has been a problem that the resistance value of the metal thin film changes, that is, the metal thin film corrodes.

On the other hand, a pressure-sensitive adhesive having at least one pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an acrylic polymer having a total content of acrylic acid and methacrylic acid of 10% by weight or less with respect to all monomer components constituting the acrylic polymer There is known a pressure-sensitive adhesive sheet, wherein the content of acrylate ions and methacrylate ions extracted from the pressure-sensitive adhesive sheet is 20 ng / cm ² or less per unit area of the pressure-sensitive adhesive layer (Patent Document 5). reference). According to this pressure-sensitive adhesive sheet, although it is a pressure-sensitive adhesive sheet made of an acrylic polymer containing acrylic acid or methacrylic acid as a monomer component, it has excellent corrosion resistance to a metal thin film such as an ITO film.

JP 2003-238915 A JP 2003-342542 A JP-A-2004-231723 JP 2013-75978 A JP 2010-195942 A

In recent years, in applications such as manufacturing of a capacitive touch panel, a film having a silver nanowire layer (AgNW layer) instead of an ITO film has been increasingly used as a metal thin film. As described above, the pressure-sensitive adhesive sheet in which the content of acrylate ions and methacrylic acid ions extracted from the pressure-sensitive adhesive sheet is 20 ng / cm ² or less per unit area of the pressure-sensitive adhesive layer is excellent in corrosion resistance to the ITO film. However, the corrosion resistance to the silver nanowire layer was not sufficient. That is, in the pressure-sensitive adhesive sheet used for sticking to an optical member having a silver nanowire layer, corrosion resistance higher than corrosion resistance to the ITO film is required. This is presumed to be because silver is easily ionized in the silver nanowire layer by acrylate ions in the pressure-sensitive adhesive layer. In addition, corrosion of the silver nanowire layer is particularly likely to be promoted by irradiation with ultraviolet rays. For this reason, at present, there is a demand for a pressure-sensitive adhesive sheet having excellent corrosion resistance to the silver nanowire layer (particularly, corrosion resistance in an environment exposed to ultraviolet rays (sometimes referred to as “UV resistance”)). .

  Accordingly, an object of the present invention is to provide an optical pressure-sensitive adhesive sheet having excellent corrosion resistance (particularly, UV resistance) to a silver nanowire layer.

  The present inventors have conducted intensive studies to achieve the above object, and have a pressure-sensitive adhesive layer, an optical pressure-sensitive adhesive sheet for a silver nanowire layer, and a very small amount of acrylate ions extracted from the pressure-sensitive adhesive layer. As a result, the present inventors have found that a pressure-sensitive adhesive sheet having excellent corrosion resistance to the silver nanowire layer can be obtained, and completed the present invention.

  That is, the present invention relates to a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, and the amount of acrylate ions extracted from the pressure-sensitive adhesive layer with pure water at 100 ° C. for 45 minutes, as measured by ion chromatography. However, the present invention provides an optical pressure-sensitive adhesive sheet for a silver nanowire layer, which is not more than 5 μg / g per 1 g of the pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive layer preferably contains an ultraviolet absorber.

  It is preferable that the absorbance A of the ultraviolet absorbent determined below is 0.5 or less. Absorbance A: Absorbance measured by exposing a 0.08% toluene solution of the ultraviolet absorber to light having a wavelength of 400 nm.

  The ultraviolet absorber is preferably at least one ultraviolet absorber selected from the group consisting of a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a hydroxyphenyltriazine-based ultraviolet absorber.

  The pressure-sensitive adhesive layer preferably contains 0.01 to 10 parts by weight of the ultraviolet absorber based on 100 parts by weight of the base polymer in the pressure-sensitive adhesive layer.

  The optical pressure-sensitive adhesive sheet is preferably an optical pressure-sensitive adhesive sheet used for a film sensor.

  The optical pressure-sensitive adhesive sheet of the present invention has excellent corrosion resistance to the silver nanowire layer. Further, it is particularly excellent in corrosion resistance in an environment where it is exposed to ultraviolet rays. For this reason, it can be preferably used for an optical member having a silver nanowire layer, in particular, for use in application to a transparent conductive film on which a silver nanowire layer such as a silver nanowire film is formed.

It is a schematic sectional view showing an example of an optical product using the optical pressure-sensitive adhesive sheet of the present invention. It is a schematic sectional drawing which shows another example of the optical product using the optical adhesive sheet of this invention. It is the schematic (top plan view) which shows the test piece used for evaluation of UV resistance of the double-sided pressure sensitive adhesive sheet produced in the Example and the comparative example. FIG. 4 is a schematic diagram (a cross-sectional view taken along line A-A ′ of FIG. 3) illustrating a test piece used for evaluating the UV resistance of the double-sided pressure-sensitive adhesive sheets manufactured in Examples and Comparative Examples.

  The optical pressure-sensitive adhesive sheet for a silver nanowire layer of the present invention has an amount of acrylate ions extracted with pure water at 100 ° C. for 45 minutes, measured by an ion chromatography method, of 5 μg per 1 g of the pressure-sensitive adhesive layer. / G or less. In addition, in this specification, the said adhesive layer may be called "the adhesive layer of this invention." In this specification, the “optical pressure-sensitive adhesive sheet for a silver nanowire layer of the present invention” may be simply referred to as the “optical pressure-sensitive adhesive sheet of the present invention”. The term "adhesive sheet" includes the meaning of "adhesive tape". That is, the optical pressure-sensitive adhesive sheet of the present invention may be a pressure-sensitive adhesive tape having a tape shape.

  In the optical pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive surface to be adhered to the silver nanowire layer side (for example, the optical member on the side where the silver nanowire layer exists in the optical product) is the pressure-sensitive adhesive surface (pressure-sensitive adhesive layer) of the present invention. As long as it is the surface of the agent layer), its form is not particularly limited. For example, it may be a single-sided pressure-sensitive adhesive sheet in which only one surface is a pressure-sensitive adhesive surface, or a double-sided pressure-sensitive adhesive sheet in which both surfaces are pressure-sensitive adhesive surfaces. When the optical pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, the optical pressure-sensitive adhesive sheet of the present invention may have a form in which both pressure-sensitive adhesive surfaces are provided by the pressure-sensitive adhesive layer of the present invention. Even if one adhesive surface is provided by the adhesive layer of the present invention and the other adhesive surface is provided by an adhesive layer other than the adhesive layer of the present invention (another adhesive layer), Good. In addition, a double-sided pressure-sensitive adhesive sheet is preferable from the viewpoint of attaching the adherends to each other.

  The optical pressure-sensitive adhesive sheet of the present invention may be a so-called “substrate-less type” pressure-sensitive adhesive sheet having no substrate (substrate layer), or a pressure-sensitive adhesive sheet having a substrate. . In this specification, the "base-less type" pressure-sensitive adhesive sheet may be referred to as a "base-less pressure-sensitive adhesive sheet", and the type of pressure-sensitive adhesive sheet having a substrate may be referred to as a "base-coated pressure-sensitive adhesive sheet". is there. Examples of the substrate-less pressure-sensitive adhesive sheet include a double-sided pressure-sensitive adhesive sheet comprising only the pressure-sensitive adhesive layer of the present invention, and a pressure-sensitive adhesive layer of the present invention and other pressure-sensitive adhesive layers (pressure-sensitive adhesive layers other than the pressure-sensitive adhesive layer of the present invention). And the like. Further, as the pressure-sensitive adhesive sheet with a substrate, for example, a single-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on one side of the substrate, a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on both sides of the substrate, And a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on one side of the substrate and another pressure-sensitive adhesive layer on the other side. The “substrate (substrate layer)” is a support, and when the optical pressure-sensitive adhesive sheet of the present invention is used (attached) to an adherend, the substrate is adhered together with the pressure-sensitive adhesive layer. This is the part that is attached to the body. The separator (release liner) that is peeled off when the pressure-sensitive adhesive sheet is used (attached) is not included in the base material.

(Adhesive layer of the present invention)
In the pressure-sensitive adhesive layer of the present invention, the amount of acrylate ions extracted from the pressure-sensitive adhesive layer with pure water at 100 ° C. for 45 minutes (meaning “extracted acrylate ion amount”) as measured by ion chromatography. Is 5 μg / g or less (eg, 0 to 5 μg / g), preferably 4.5 μg / g or less (eg, 0 to 4.5 μg / g), more preferably 1 g / g of the pressure-sensitive adhesive layer. 4 μg / g or less (for example, 0 to 4 μg / g), more preferably 3.2 μg / g or less (for example, 0 to 3.2 μg / g), particularly preferably 3 μg / g or less (for example, 0 to 3 μg / g) ), And most preferably 2.5 μg / g or less (eg, 0 to 2.5 μg / g). The above-mentioned extracted acrylate ion amount indicates the degree of ease of release of acrylate ions from the pressure-sensitive adhesive layer by moisture when the pressure-sensitive adhesive sheet is placed in a humid environment or the like. When the amount of the extracted acrylate ion exceeds 5 μg / g, the pressure-sensitive adhesive sheet of the present invention is adhered to the optical member on the side where the silver nanowire layer is present, and the water content under the humidifying condition or the like is adhered. When stored in the presence, the silver nanowire layer is corroded due to the effect of acrylate ions released from the pressure-sensitive adhesive layer, the resistance value increases, and the conductivity tends to decrease.

The above “extracted acrylic acid ion amount” can be measured by the following method.
First, a pressure-sensitive adhesive layer was cut into an appropriate size, a PET film (25 to 50 μm in thickness) was stuck on one of the pressure-sensitive adhesive surfaces of the pressure-sensitive adhesive layer, and only one of the pressure-sensitive adhesive surfaces was exposed. And In addition, when the optical pressure-sensitive adhesive sheet of the present invention is a single-sided pressure-sensitive adhesive sheet with a base material, the test piece in a state where the release liner is peeled off may be used as necessary. In addition, when the optical pressure-sensitive adhesive sheet of the present invention is a substrate-less type double-sided pressure-sensitive adhesive sheet comprising one pressure-sensitive adhesive layer, a test piece in which a release liner is provided on one surface of the pressure-sensitive adhesive layer is used as a test piece. May be used. The exposed area of the adhesive surface of the test piece is preferably 100 cm ² .
Next, the test piece is placed in pure water at a temperature of 100 ° C. and boiled for 45 minutes to perform boiling extraction of acrylate ions.
Next, the amount (unit: μg) of acrylate ions in the extract obtained above was measured by ion chromatography (ion chromatography), and the amount of acrylate ions per 1 g of the pressure-sensitive adhesive layer in the test piece was measured. (Unit: μg / g) is calculated. The measurement conditions of the ion chromatography (ion chromatography) are not particularly limited, but, for example, can be measured under the following conditions.
[Measurement conditions for ion chromatography]
Analyzer: Thermo Fisher Scientific, ICS-3000
Separation column: Ion Pac AS18 (4 mm x 250 mm)
Guard column: Ion Pac AG18 (4 mm x 50 mm)
Removal system: AERS-500 (External mode)
Detector: Electric conductivity detector Eluent: KOH aqueous solution
(Using eluent generator EGIII)
Eluent flow rate: 1.0 ml / min Sample injection volume: 250 μl

  The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the present invention is not particularly limited, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyamide-based pressure-sensitive adhesive Adhesives, urethane-based adhesives, fluorine-based adhesives, epoxy-based adhesives, and the like can be given. Above all, as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, an acrylic pressure-sensitive adhesive is preferable in terms of transparency, tackiness, weather resistance, cost, and ease of designing the pressure-sensitive adhesive. That is, the pressure-sensitive adhesive layer of the present invention is preferably an acrylic pressure-sensitive adhesive layer composed of an acrylic pressure-sensitive adhesive. The above-mentioned pressure-sensitive adhesives can be used alone or in combination of two or more.

  The acrylic pressure-sensitive adhesive layer contains an acrylic polymer as a base polymer. The acrylic polymer is a polymer containing an acrylic monomer (monomer having a (meth) acryloyl group in the molecule) as a monomer component constituting the polymer. The acrylic polymer is preferably a polymer containing an alkyl (meth) acrylate as a monomer component constituting the polymer. The acrylic polymers can be used alone or in combination of two or more.

  The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer of the present invention may be in any form. For example, the pressure-sensitive adhesive composition may be an emulsion type, a solvent type (solution type), an active energy ray-curable type, a hot melt type (hot melt type), or the like. Above all, a solvent type and an active energy ray-curable pressure-sensitive adhesive composition are preferable in terms of productivity and a point that a pressure-sensitive adhesive layer excellent in optical characteristics and appearance is easily obtained. In particular, a solvent-type pressure-sensitive adhesive composition is preferable from the viewpoint that the amount of acrylate ions in the pressure-sensitive adhesive layer can be further reduced.

  That is, the pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer as a base polymer, and is preferably formed of a solvent-type acrylic pressure-sensitive adhesive composition.

  Examples of the active energy rays include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, electron beams, and ultraviolet rays, and ultraviolet rays are particularly preferable. That is, the active energy ray-curable pressure-sensitive adhesive composition is preferably an ultraviolet-curable pressure-sensitive adhesive composition.

  As the pressure-sensitive adhesive composition (acrylic pressure-sensitive adhesive composition) for forming the acrylic pressure-sensitive adhesive layer, for example, an acrylic pressure-sensitive adhesive composition containing an acrylic polymer as an essential component, or a simple composition comprising the acrylic polymer. An acrylic pressure-sensitive adhesive composition containing a mixture of monomers (sometimes referred to as a “monomer mixture”) or a partial polymer thereof as an essential component is exemplified. The former includes, for example, a so-called solvent-type acrylic pressure-sensitive adhesive composition. Also. Examples of the latter include a so-called active energy ray-curable acrylic pressure-sensitive adhesive composition. The above “monomer mixture” means a mixture containing a monomer component constituting a polymer. Further, the “partially polymerized product” may be referred to as a “prepolymer”, and means a composition in which one or two or more monomer components of the monomer components in the monomer mixture are partially polymerized. I do.

  The acrylic polymer is a polymer constituted (formed) of an acrylic monomer as an essential monomer component (monomer component). The acrylic polymer is preferably a polymer constituted (formed) of an alkyl (meth) acrylate as an essential monomer component. That is, the acrylic polymer preferably contains an alkyl (meth) acrylate as a constituent unit. In this specification, “(meth) acryl” refers to “acryl” and / or “methacryl” (either or both of “acryl” and “methacryl”), and the same applies to the others. The acrylic polymer is composed of one or more monomer components.

  Preferred examples of the alkyl (meth) acrylate as an essential monomer component include alkyl (meth) acrylates having a linear or branched alkyl group. The alkyl (meth) acrylates can be used alone or in combination of two or more.

  Examples of the alkyl (meth) acrylate having a linear or branched alkyl group include, but are not particularly limited to, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and ( Isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, (meth) Isopentyl acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, (meth) acrylate ) Isononyl acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, Undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, (meth) ) A linear or branched alkyl group having 1 to 20 carbon atoms such as octadecyl acrylate (stearyl (meth) acrylate), isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate (Meth) acrylic acid alkyl ester having the formula: Among them, the (meth) acrylic acid alkyl ester having a linear or branched alkyl group is preferably a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms. And more preferably 2-ethylhexyl acrylate (2EHA) and isostearyl acrylate (ISTA). The alkyl (meth) acrylate having a linear or branched alkyl group may be used alone or in combination of two or more.

  The proportion of the alkyl (meth) acrylate in all the monomer components (100% by weight) constituting the acrylic polymer is not particularly limited, but is 50% by weight or more (for example, 50 to 100% by weight). It is preferably 53 to 90% by weight, more preferably 55 to 85% by weight.

  The acrylic polymer may contain a copolymerizable monomer together with the alkyl (meth) acrylate as a monomer component constituting the polymer. That is, the acrylic polymer may include a copolymerizable monomer as a structural unit. The copolymerizable monomers can be used alone or in combination of two or more.

  Examples of the copolymerizable monomer include, but are not particularly limited to, suppression of clouding in a high-humidity environment and improvement in durability, adhesion reliability to a silver nanowire layer and a protective layer described below, and various additives such as an ultraviolet absorber. From the viewpoint of compatibility and transparency, a monomer having a nitrogen atom in the molecule and a monomer having a hydroxyl group in the molecule are preferred. That is, the acrylic polymer preferably contains, as a structural unit, a monomer having a nitrogen atom in the molecule. The acrylic polymer preferably contains, as a structural unit, a monomer having a hydroxyl group in the molecule.

  The monomer having a nitrogen atom in the molecule is a monomer (monomer) having at least one nitrogen atom in the molecule (in one molecule). In the present specification, the “monomer having a nitrogen atom in the molecule” may be referred to as a “nitrogen atom-containing monomer”. The nitrogen atom-containing monomer is not particularly limited, but preferably includes a cyclic nitrogen-containing monomer, (meth) acrylamides and the like. The nitrogen atom-containing monomers can be used alone or in combination of two or more.

  The cyclic nitrogen-containing monomer is not particularly limited as long as it has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and has a cyclic nitrogen structure. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure.

  Examples of the cyclic nitrogen-containing monomer include an N-vinyl cyclic amide (lactam-based vinyl monomer) and a vinyl-based monomer having a nitrogen-containing heterocycle.

（式（１）中、Ｒ¹は２価の有機基を示す） Examples of the N-vinyl cyclic amide include an N-vinyl cyclic amide represented by the following formula (1).

(In the formula (1), R ¹ represents a divalent organic group.)

R ¹ in the above formula (1) is a divalent organic group, preferably a divalent saturated hydrocarbon group or an unsaturated hydrocarbon group, and more preferably a divalent saturated hydrocarbon group (for example, And 3-5 alkylene groups).

  Examples of the N-vinyl cyclic amide represented by the above formula (1) include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, and N-vinyl-2-caprolactam. , N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione and the like.

  Examples of the vinyl monomer having a nitrogen-containing hetero ring include acrylic monomers having a nitrogen-containing hetero ring such as a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring.

  The vinyl-based monomer having a nitrogen-containing heterocyclic ring is not particularly limited. For example, (meth) acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-vinylpyrazine, N-vinylmorpholine , N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinyloxazole, vinylisoxazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth) acryloylpyrrolidone, (meth) acryloylpyrrolidine, (meth) acryloylpiperidine and the like. .

  Among the vinyl monomers having a nitrogen-containing heterocycle, acrylic monomers having a nitrogen-containing heterocycle are preferable, and (meth) acryloylmorpholine, (meth) acryloylpyrrolidine, and (meth) acryloylpiperidine are more preferable.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-alkyl (meth) acrylamide, and N, N-dialkyl (meth) acrylamide. Examples of the N-alkyl (meth) acrylamide include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, N-octyl (meth) acrylamide, and the like. . Furthermore, the above-mentioned N-alkyl (meth) acrylamide also includes (meth) acrylamide having an amino group such as dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, and dimethylaminopropyl (meth) acrylamide. Examples of the N, N-dialkyl (meth) acrylamide include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (Meth) acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide and the like.

  The (meth) acrylamides also include, for example, various N-hydroxyalkyl (meth) acrylamides. Examples of the N-hydroxyalkyl (meth) acrylamide include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N-methyl-N-2-hydroxyethyl (meth) acrylamide and the like can be mentioned.

  The (meth) acrylamides also include, for example, various N-alkoxyalkyl (meth) acrylamides. Examples of the N-alkoxyalkyl (meth) acrylamide include N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, and the like.

  Examples of the nitrogen-containing monomer other than the cyclic nitrogen-containing monomer and the (meth) acrylamide include, for example, an amino group-containing monomer, a cyano group-containing monomer, an imide group-containing monomer, and an isocyanate group-containing monomer. Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate. . Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the imide group-containing monomer include a maleimide-based monomer (eg, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, etc.) and an itaconimide-based monomer (eg, N-methylitaconimide, N- Ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-lauryl itacon imide, N-cyclohexyl itacon imide, etc., succinimide monomers (for example, N- (meth) acryloyl) Oxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide, etc.). Examples of the isocyanate group-containing monomer include 2- (meth) acryloyloxyethyl isocyanate.

  Above all, as the nitrogen atom-containing monomer, a cyclic nitrogen-containing monomer is preferable, and N-vinyl cyclic amide is more preferable. More specifically, N-vinyl-2-pyrrolidone (NVP) is particularly preferred.

  When the acrylic polymer contains the nitrogen atom-containing monomer as a monomer component constituting the polymer, the proportion of the nitrogen atom-containing monomer in all monomer components (100% by weight) constituting the acrylic polymer is as follows: Although not particularly limited, it is preferably 1% by weight or more, more preferably 3% by weight or more, and still more preferably 5% by weight or more. When the proportion is 1% by weight or more, the proportion of the monomer having a hydroxyl group in the molecule can be reduced, so that the amount of acrylate ions derived from the monomer having a hydroxyl group in the molecule can be further reduced. Tend to be preferred. Further, the suppression of clouding in a high humidity environment and the durability are further improved, and higher adhesion reliability to the silver nanowire layer and a protective layer described later can be obtained, which is preferable. The upper limit of the proportion of the nitrogen atom-containing monomer is preferably 30% by weight or less, more preferably 25% by weight, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate flexibility and obtaining a pressure-sensitive adhesive layer having excellent transparency. %, More preferably 20% by weight or less.

  The monomer having a hydroxyl group in the molecule is a monomer having at least one hydroxyl group (hydroxyl group) in the molecule (in one molecule), and is a polymer having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Those having an acidic functional group and having a hydroxyl group are preferred. However, the monomer having a hydroxyl group in the molecule does not include the nitrogen atom-containing monomer. That is, in the present specification, a monomer having both a nitrogen atom and a hydroxyl group in a molecule is included in the “nitrogen atom-containing monomer”. In the present specification, the above “monomer having a hydroxyl group in the molecule” may be referred to as “hydroxyl group-containing monomer”. The hydroxyl group-containing monomers can be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, Hydroxyl-containing such as 6-hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) (meth) acrylate ( (Meth) acrylic acid esters; vinyl alcohol; allyl alcohol and the like.

  Among them, as the hydroxyl group-containing monomer, a hydroxyl group-containing (meth) acrylic acid ester is preferable, and 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) are more preferable.

  When the acrylic polymer contains the hydroxyl group-containing monomer as a monomer component constituting the polymer, the proportion of the hydroxyl group-containing monomer in all monomer components (100% by weight) constituting the acrylic polymer is particularly limited. However, it is preferably 0.5% by weight or more from the viewpoint of suppressing white turbidity and improving durability under a high humidity environment and obtaining higher adhesion reliability to a silver nanowire layer and a protective layer described below. It is more preferably at least 0.8% by weight, and even more preferably at least 1% by weight. The upper limit of the proportion of the hydroxyl group-containing monomer is preferably 30% by weight or less, more preferably 25% by weight or less, and further preferably 15% by weight or less. When the ratio is 30% by weight or less (particularly 25% by weight or less), the amount of acrylate ions derived from the hydroxyl group-containing monomer tends to be able to be further reduced, which is preferable. It is presumed that acrylate ions derived from the hydroxyl group-containing monomer are necessarily mixed in when the hydroxyl group-containing monomer is used as a monomer component constituting the polymer. This is presumably because acrylic acid ions were mixed in the process of producing the hydroxyl group-containing monomer, and acrylic acid ions were present at a certain rate as impurities in commercially available products. When the pressure-sensitive adhesive layer of the present invention is formed of an active energy ray-curable pressure-sensitive adhesive composition, the ratio of the hydroxyl group-containing monomer in all the monomer components (100% by weight) constituting the acrylic polymer is determined. The upper limit is preferably 10% by weight or less, more preferably 5% by weight or less, from the viewpoint of reducing the amount of acrylate ions in the pressure-sensitive adhesive layer.

  The total of the proportions of the nitrogen atom-containing monomer and the hydroxyl group-containing monomer in all the monomer components (100% by weight) constituting the acrylic polymer is not particularly limited, but is not limited to white turbidity in a high humidity environment. It is preferably at least 5% by weight, more preferably at least 10% by weight, even more preferably at least 15% by weight, from the viewpoint of improving durability and obtaining higher adhesion reliability to the silver nanowire layer and the protective layer described below. That is all. Further, the upper limit of the total of the above ratios is preferably 50% by weight or less, more preferably 40% by weight, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate flexibility and obtaining a pressure-sensitive adhesive layer having excellent transparency. %, More preferably 35% by weight or less.

  The copolymerizable monomer other than the nitrogen atom-containing monomer and the hydroxyl group-containing monomer further includes an alicyclic structure-containing monomer. The alicyclic structure-containing monomer is not particularly limited as long as it has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and has an alicyclic structure. For example, an alkyl (meth) acrylate having a cycloalkyl group is included in the alicyclic structure-containing monomer. In addition, the alicyclic structure-containing monomer can be used alone or in combination of two or more.

  The alicyclic structure in the alicyclic structure-containing monomer is a cyclic hydrocarbon structure, preferably having 5 or more carbon atoms, more preferably 6 to 24 carbon atoms, still more preferably 6 to 15 carbon atoms, 6 to 10 are particularly preferred.

Examples of the alicyclic structure-containing monomer include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, Isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, HPPMA represented by the following formula (2), TMA-2 represented by the following formula (3), HCPA represented by the following formula (4), and the like. (Meth) acrylic monomers. In the following formula (4), the bonding site between the cyclohexyl ring connected by a line and the structural formula in parentheses is not particularly limited. Among these, isobornyl (meth) acrylate is preferred.

  When the acrylic polymer contains the alicyclic structure-containing monomer as a monomer component constituting the polymer, the proportion of the alicyclic structure-containing monomer in all the monomer components (100% by weight) constituting the acrylic polymer Is not particularly limited, but is preferably 10% by weight or more from the viewpoint of improving durability and obtaining higher adhesion reliability to a silver nanowire layer and a protective layer described below. Further, the upper limit of the proportion of the alicyclic structure-containing monomer is preferably 50% by weight or less, more preferably 40% by weight or less, and still more preferably 30% by weight or less from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate flexibility. It is.

  Further, examples of the copolymerizable monomer include a polyfunctional monomer. Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, Examples include allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. The polyfunctional monomers can be used alone or in combination of two or more.

  When the acrylic polymer contains the polyfunctional monomer as a monomer component constituting the polymer, the proportion of the polyfunctional monomer in all the monomer components (100% by weight) constituting the acrylic polymer is as follows: Although not particularly limited, it is preferably 0.5% by weight or less (for example, more than 0% by weight and 0.5% by weight or less), and more preferably 0.2% by weight or less (for example, more than 0% by weight and 0.1% by weight or less). 2% by weight or less).

  Examples of the copolymerizable monomer include alkoxyalkyl (meth) acrylate. Examples of the alkoxyalkyl (meth) acrylate include, but are not particularly limited to, for example, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ( Examples thereof include 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, and 4-ethoxybutyl (meth) acrylate. Among them, the alkoxyalkyl (meth) acrylate is preferably an alkoxyalkyl acrylate, and more preferably 2-methoxyethyl acrylate (MEA). In addition, the said (meth) acrylic-acid alkoxyalkyl ester can be used individually or in combination of 2 or more types.

  When the acrylic polymer contains the (meth) acrylic acid alkoxyalkyl ester as a monomer component constituting the polymer, the ratio of the (meth) acrylic acid alkyl ester and the (meth) acrylic acid alkoxyalkyl ester is as follows: Although not particularly limited, the ratio is more preferably more than 100: 0 and not more than 25:75, more preferably more than 100: 0 and not more than 50:50.

  In addition, examples of the copolymerizable monomer include a carboxyl group-containing monomer, an epoxy group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a (meth) acrylate having an aromatic hydrocarbon group, Examples include vinyl esters, aromatic vinyl compounds, olefins or dienes, vinyl ethers, and vinyl chloride. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. Examples of the carboxyl group-containing monomer include maleic anhydride And acid anhydride group-containing monomers such as itaconic anhydride. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate. Examples of the sulfonic acid group-containing monomer include sodium vinyl sulfonate. Examples of the (meth) acrylate having an aromatic hydrocarbon group include phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and benzyl (meth) acrylate. Examples of the vinyl esters include vinyl acetate and vinyl propionate. Examples of the aromatic vinyl compound include styrene and vinyl toluene. Examples of the olefins or dienes include ethylene, propylene, butadiene, isoprene, isobutylene, and the like. Examples of the vinyl ethers include vinyl alkyl ethers.

  The acrylic polymer does not contain or substantially does not contain an acidic group-containing monomer as a monomer component constituting the polymer, from the viewpoint of obtaining an acrylic pressure-sensitive adhesive layer having excellent corrosion resistance to the silver nanowire layer. It is particularly preferable that no or substantially no carboxyl group-containing monomer is contained. Examples of the acidic group-containing monomer include a carboxyl group-containing monomer, a sulfonic acid group-containing monomer, and a phosphate group-containing monomer. Specifically, the ratio of the acidic group-containing monomer in all the monomer components (100% by weight) constituting the acrylic polymer is 0.05% by weight or less (preferably 0.01% by weight or less). Can be substantially not contained.

  Although not particularly limited, the acrylic polymer includes, as a monomer component constituting the polymer, a monomer having a high glass transition temperature (Tg) when a homopolymer is formed (hereinafter, may be referred to as “high Tg monomer”). Preferably, it is included. When a high Tg monomer is used as the monomer component, the pressure-sensitive adhesive containing the acrylic polymer becomes harder, and the adhesion reliability of the optical pressure-sensitive adhesive sheet of the present invention to a silver nanowire layer or a protective layer described below at a high temperature is more improved. Improved and preferred.

  The glass transition temperature when the high Tg monomer homopolymer is formed is not particularly limited, but is, for example, 20 ° C. or higher, preferably 30 ° C. or higher, more preferably 90 ° C. or higher. When the Tg of the high Tg monomer is in the above range, the cohesive force of the pressure-sensitive adhesive layer increases.

  The high Tg monomer may be the above-mentioned monomer exemplified as the monomer contained in the monomer component constituting the acrylic polymer, or may be another monomer. In particular, the monomer component constituting the acrylic polymer is preferably the monomer exemplified as the monomer component constituting the acrylic polymer described above, and preferably contains a monomer component that is a high Tg monomer. The high Tg monomer may be only one kind or two or more kinds.

  Examples of the high Tg monomer include, but are not particularly limited to, methyl methacrylate (Tg: 105 ° C), ethyl methacrylate (Tg: 65 ° C), cyclohexyl methacrylate (Tg: 83 ° C), and isobornyl acrylate (Tg: 94 ° C.), isobornyl methacrylate (Tg: 150 ° C.), benzyl methacrylate (Tg: 54 ° C.), glycidyl methacrylate (Tg: 46 ° C.), stearyl methacrylate (Tg: 38 ° C.), 3-hydroxypropyl methacrylate (Tg: 26 ° C.), 2-hydroxyethyl methacrylate (Tg: 55 ° C.), acrylic acid (Tg: 106 ° C.), methacrylic acid (Tg: 227 ° C.), and the like. In addition to the above, for example, vinyl acetate (Tg: 32 ° C.), acrylonitrile (Tg: 97 ° C.), methacrylonitrile (Tg: 120 ° C.), styrene (Tg: 80 ° C.), 2-methylstyrene (Tg : 136 ° C), acrylamide (Tg: 165 ° C), N-vinyl-2-pyrrolidone (NVP) (Tg: 80 ° C) and the like. Among them, methyl methacrylate, isobornyl acrylate, and NVP are preferred.

  When the acrylic polymer contains the high Tg monomer as a monomer component constituting the polymer, the proportion of the high Tg monomer in all the monomer components (100% by weight) constituting the acrylic polymer is particularly limited. However, it is preferably 1 to 50% by weight, more preferably 5 to 40% by weight, and still more preferably 10 to 30% by weight. When the proportion of the high Tg monomer is in the above range, the adhesion reliability of the optical pressure-sensitive adhesive sheet of the present invention to a silver nanowire layer or a protective layer described below at a high temperature is further improved, which is preferable. When two or more high Tg monomers are contained in the monomer component constituting the polymer, the “ratio of high Tg monomer” is the sum of the ratios of the two or more high Tg monomers.

  Among the above acrylic polymers, among the above, 50 to 90% by weight (preferably 55 to 85% by weight) of a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms. ), At least one monomer selected from the group consisting of a nitrogen atom-containing monomer and a hydroxyl group-containing monomer in an amount of 10 to 50% by weight (preferably 15 to 40% by weight) and an alicyclic structure-containing monomer having 6 to 10 carbon atoms. Is preferably an acrylic polymer composed of a monomer mixture containing 0 to 40% by weight (preferably 0 to 30% by weight), and has a linear or branched alkyl group having 4 to 18 carbon atoms ( The alkyl (meth) acrylate is 50 to 90% by weight (preferably 55 to 85% by weight), and the nitrogen-containing monomer is 3 to 30% by weight (preferably 5 to 25% by weight). %), The hydroxyl group-containing monomer is 0.8 to 25% by weight (preferably 1 to 15% by weight), and the alicyclic structure-containing monomer having 6 to 10 carbon atoms is 0 to 40% by weight (preferably 0 to 30% by weight). ) Is more preferably an acrylic polymer composed of a monomer mixture in which the total of the proportions of the nitrogen atom-containing monomer and the hydroxyl group-containing monomer is 10 to 50% by weight (preferably 15 to 40% by weight). The above ratio (% by weight) is a ratio with respect to all monomer components (100% by weight) constituting the acrylic polymer.

  Although the content of the base polymer (especially acrylic polymer) in the pressure-sensitive adhesive layer of the present invention is not particularly limited, it is 50% by weight or more (for example, 50% by weight) based on 100% by weight of the total weight of the pressure-sensitive adhesive layer of the present invention. To 100% by weight), more preferably 80% by weight or more (for example, 80 to 100% by weight), and still more preferably 90% by weight or more (for example, 90 to 100% by weight).

  The base polymer such as the acrylic polymer contained in the pressure-sensitive adhesive layer of the present invention is obtained by polymerizing a monomer component. The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method using active energy ray irradiation (active energy ray polymerization method). Among them, a solution polymerization method and an active energy ray polymerization method are preferable from the viewpoint of transparency and cost of the pressure-sensitive adhesive layer, and a solution polymerization method is more preferable from the viewpoint of reducing the amount of acrylate ions in the pressure-sensitive adhesive layer.

  In the polymerization of the above monomer components, various general solvents may be used. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane. And organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. The solvents may be used alone or in combination of two or more.

  Upon polymerization of the above monomer components, a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) may be used depending on the type of the polymerization reaction. The polymerization initiator can be used alone or in combination of two or more.

  Although it does not specifically limit as said thermal-polymerization initiator, For example, an azo-type polymerization initiator, a peroxide-type polymerization initiator (for example, dibenzoyl peroxide, tert-butyl permaleate, etc.), a redox-type polymerization initiator, etc. Is mentioned. Among them, the azo-based polymerization initiator disclosed in JP-A-2002-69411 is preferable. Examples of the azo-based polymerization initiator include 2,2′-azobisisobutyronitrile (hereinafter sometimes referred to as “AIBN”) and 2,2′-azobis-2-methylbutyronitrile (hereinafter, referred to as “AIBN”). AMBN "), 2,2'-azobis (2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, and the like. The thermal polymerization initiator can be used alone or in combination of two or more.

  When using the azo polymerization initiator during the polymerization of the acrylic polymer, the amount of the azo polymerization initiator used is not particularly limited, for example, 100 parts by weight of all monomer components constituting the acrylic polymer Is preferably at least 0.05 part by weight, more preferably at least 0.1 part by weight, and preferably at most 0.5 part by weight, more preferably 0.3 part by weight. It is as follows.

The photopolymerization initiator is not particularly limited, for example, benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α-ketol-based photopolymerization initiator, aromatic sulfonyl chloride-based photopolymerization initiator, light Examples of the active oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzyl-based photopolymerization initiator, benzophenone-based photopolymerization initiator, ketal-based photopolymerization initiator, and thioxanthone-based photopolymerization initiator. Other examples include acylphosphine oxide-based photopolymerization initiators and titanocene-based photopolymerization initiators. Examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one, Anisole methyl ether and the like can be mentioned. Examples of the acetophenone-based photopolymerization initiator include, for example, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). ) Dichloroacetophenone and the like. Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one, and the like. Can be Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (O-ethoxycarbonyl) -oxime. Examples of the benzoin-based photopolymerization initiator include benzoin and the like. Examples of the benzyl-based photopolymerization initiator include benzyl and the like. Examples of the benzophenone-based photopolymerization initiator include, for example, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenyl ketone, and the like. Examples of the ketal-based photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like. Examples of the acylphosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. . Examples of the titanocene-based photopolymerization initiator include, for example, bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl ) Titanium and the like. The photopolymerization initiators can be used alone or in combination of two or more.

  When using the photopolymerization initiator during the polymerization of the acrylic polymer, the amount of the photopolymerization initiator is not particularly limited, for example, based on 100 parts by weight of all monomer components constituting the acrylic polymer It is preferably 0.01 part by weight or more, more preferably 0.1 part by weight or more, and preferably 3 parts by weight or less, more preferably 1.5 parts by weight or less.

  Although not particularly limited, the pressure-sensitive adhesive layer of the present invention preferably contains an ultraviolet absorber (UVA). When the pressure-sensitive adhesive layer of the present invention contains an ultraviolet absorber, the amount of extracted acrylic acid ions tends to be able to be further reduced. In particular, when the pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer formed from a solvent-type pressure-sensitive adhesive composition, it preferably contains an ultraviolet absorber. In addition, an ultraviolet absorber can be used individually or in combination of 2 or more types.

  Examples of the ultraviolet absorber include, but are not particularly limited to, for example, benzotriazole ultraviolet absorber, hydroxyphenyltriazine ultraviolet absorber, benzophenone ultraviolet absorber, salicylate ultraviolet absorber, cyanoacrylate ultraviolet absorber, oxy A benzophenone-based ultraviolet absorber is exemplified.

  Examples of the benzotriazole-based ultraviolet absorber (benzotriazole-based compound) include 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), benzene Ester compounds of propanoic acid and 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and linear alkyl) (trade name "TINUVIN 384") -2 ", manufactured by BASF), octyl 3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [ 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazo 2- (2yl) phenyl] propionate (trade name “TINUVIN 109”, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) ) Phenol (trade name "TINUVIN 900", manufactured by BASF), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3) 3-tetramethylbutyl) phenol (trade name "TINUVIN 928", manufactured by BASF), methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene Glycol 300 reaction product (trade name “TINUVIN 1130”, manufactured by BASF), 2- (2H-benzotriene) Zol-2-yl) -p-cresol (trade name “TINUVIN P”, manufactured by BASF), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) ) Phenol (trade name “TINUVIN 234”, manufactured by BASF), 2- [5-chloro-2H-benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (trade name “TINUVIN 326”) , BASF), 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol (trade name "TINUVIN 328", BASF), 2- (2H-benzotriazole) -2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (trade name "TINUVIN 329", manufactured by BASF) , 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] (trade name "TINUVIN 360", manufactured by BASF) Reaction product of methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by BASF) ), 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol (trade name “TINUVIN 571”, manufactured by BASF), 2- [2-hydroxy-3- (3,4, 5,6-tetrahydrophthalimide-methyl) -5-methylphenyl] benzotriazole (trade name "Sumisorb 25 , Manufactured by Sumitomo Chemical Co., Ltd.), 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol] (trade name "ADEKA STAB LA-31", ADEKA CORPORATION) Manufactured).

Examples of the hydroxyphenyltriazine-based ultraviolet absorber (hydroxyphenyltriazine-based compound) include 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5. Reaction product of -hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy) methyl] oxirane (trade name “TINUVIN 400”, manufactured by BASF), 2- [4,6-bis (2, 4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4, Reaction product of 6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester ( Trade name “TINUVIN 405”, manufactured by BASF), 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (trade name) “TINUVIN 460”, manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol (trade name “TINUVIN 1577”, BASF), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy] -phenol (trade name "ADEKA STAB LA") -46 ", manufactured by ADEKA Corporation), 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl) -1 , 3,5-triazine (trade name "TINUVIN 479", manufactured by BASF). Other examples include a compound represented by the following formula (5) (trade name “TINUVIN 477”, manufactured by BASF).

  Examples of the benzophenone-based ultraviolet absorber (benzophenone-based compound) and the oxybenzophenone-based ultraviolet absorber (oxybenzophenone-based compound) include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4- Methoxybenzophenone-5-sulfonic acid (anhydride and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2′- Dihydroxy-4-methoxybenzophenone (trade name "KEMISORB 111", manufactured by Chemipro Kasei Co., Ltd.), 2,2 ', 4,4'-tetrahydroxybenzophenone (trade name "SEESORB 106", manufactured by Cipro Kasei Co., Ltd.) , 2 Such as 2'-dihydroxy-4,4'-dimethoxy benzophenone.

  Examples of the salicylate-based ultraviolet absorbers (salicylate-based compounds) include, for example, phenyl 2-acryloyloxybenzoate, phenyl 2-acryloyloxy-3-methylbenzoate, phenyl 2-acryloyloxy-4-methylbenzoate, and phenyl 2- Acryloyloxy-5-methylbenzoate, phenyl 2-acryloyloxy-3-methoxybenzoate, phenyl 2-hydroxybenzoate, phenyl 2-hydroxy-3-methylbenzoate, phenyl 2-hydroxy-4-methylbenzoate, phenyl 2-hydroxy- 5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo Over door (trade name "TINUVIN 120", manufactured by BASF), and the like.

  Examples of the cyanoacrylate ultraviolet absorber (cyanoacrylate compound) include alkyl 2-cyanoacrylate, cycloalkyl 2-cyanoacrylate, alkoxyalkyl 2-cyanoacrylate, alkenyl 2-cyanoacrylate, alkynyl 2-cyanoacrylate, and the like. No.

  As the above-mentioned ultraviolet absorber, a pressure-sensitive adhesive layer having high ultraviolet absorption, further improving the corrosion resistance (particularly, UV resistance) of the silver nanowire layer, excellent optical properties, and high transparency At least one kind of ultraviolet absorption selected from the group consisting of benzotriazole-based UV absorbers, benzophenone-based UV absorbers, and hydroxyphenyltriazine-based UV absorbers in terms of ease of obtaining and excellent light stability Agents are preferred, and benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers are more preferred. In particular, a benzotriazole ultraviolet absorber in which a phenyl group having a group having 6 or more carbon atoms and a hydroxyl group as a substituent is bonded to a nitrogen atom constituting a benzotriazole ring is preferable.

In addition, the above-mentioned ultraviolet absorber obtains higher ultraviolet absorptivity and further improves corrosion resistance (particularly, UV resistance) of the silver nanowire layer. Preferably, there is.
Absorbance A: Absorbance measured by exposing a 0.08% toluene solution of the ultraviolet absorber to light having a wavelength of 400 nm.

  When the pressure-sensitive adhesive layer of the present invention contains an ultraviolet absorbent, the content of the ultraviolet absorbent in the pressure-sensitive adhesive layer of the present invention (particularly, acrylic pressure-sensitive adhesive layer) is not particularly limited, but the extracted acrylic acid ion content Is preferably 0.01 part by weight or more, more preferably 0.05 part by weight or more, and still more preferably 0.1 part by weight, based on 100 parts by weight of the base polymer. Parts or more. In addition, the upper limit of the content of the ultraviolet absorber suppresses the yellowing phenomenon of the pressure-sensitive adhesive caused by the addition of the ultraviolet absorber, and provides excellent optical properties, high transparency, and excellent appearance properties. Thus, the amount is preferably 10 parts by weight or less, more preferably 9 parts by weight or less, and still more preferably 8 parts by weight or less based on 100 parts by weight of the base polymer.

  The pressure-sensitive adhesive layer of the present invention may contain a light stabilizer. When the pressure-sensitive adhesive layer of the present invention contains a light stabilizer, it is particularly preferable to contain a light stabilizer together with the ultraviolet absorber. The light stabilizer can capture radicals generated by photo-oxidation, so that the pressure-sensitive adhesive layer can have improved resistance to light (particularly, ultraviolet light). The light stabilizers can be used alone or in combination of two or more.

  Although it does not specifically limit as said light stabilizer, For example, a phenol type light stabilizer (phenol type compound), a phosphorus type light stabilizer (phosphorus type compound), a thioether type light stabilizer (thioether type compound), an amine type light Stabilizers (amine compounds) (especially hindered amine stabilizers (hindered amine compounds)) and the like.

  Examples of the phenolic light stabilizer (phenolic compound) include 2,6-di-tertiary butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tertiary butylphenol, 6-di-tert-butyl-4-ethylphenol, butylated hydroxyanisole, n-octadecyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate, distearyl (4-hydroxy- 3-methyl-5-tert-butyl) benzylmalonate, tocopherol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert. Tertiary butylphenol), 4,4'-methylenebis (2,6-di-tertiary butylphenol), 4,4'-butylidenebis (6-tertiary butyl) m-cresol), 4,4'-thiobis (6-tert-butyl-m-cresol), styrenated phenol, N, N'-hexamethylenebis (3,5-di-tert-butyl-4-) Hydroxyhydrocinnamide, bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester) calcium, 1,1,3-tris (2-methyl-4-hydroxy-5-tertiary Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [3- (3,5-di- Tertiary butyl-4-hydroxyphenyl) propionyloxymethyl] methane, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'-methylenebis [6- (1-methylcyclohexyl) -p-cresol], 1,3,5-tris (4- Tertiary butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, triethylene glycol- Bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 2,2'-oxamidobis [ethyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate], 6- (4-hydroxy-3,5-di-tert-butylanilino) -2,4-dioctylthio-1,3,5-triazine, bis [2-tertiary) Tyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-) (Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis {2- [3- (3 , 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5.5] undecane.

  Examples of the phosphorus-based light stabilizer (phosphorus-based compound) include trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, and tris [2-tert-butyl-4- ( 3-tert-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) penta Erythritol diphosphite, distearylpentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6- Di-tert-butyl-4-methylphenyl) pentaerythritol dipho Phyte, bis (2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidenediphenol diphosphite, tetra (tridecyl) -4,4′-n-butylidenebis ( 2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butanetriphosphite, tetrakis (2 , 4-di-tert-butylphenyl) biphenylenediphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris (2-[(2,4,8, 10-tetrakis-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepin-6-yl) o Shi] ethyl) such as amines.

  Examples of the thioether-based light stabilizer (thioether-based compound) include dialkylthiodipropionate compounds such as dilauryl thiodipropionate, dimyristyl, and distearyl; and polyol β such as tetrakis [methylene (3-dodecylthio) propionate] methane. -Alkyl mercaptopropionate compounds and the like.

  Examples of the amine light stabilizer (amine compound) include, for example, a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (trade name “TINUVIN 622”, BASF Co., Ltd.), a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and N, N ′, N ″, N ′ ″-tetrakis- (4, 6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine and 1: 1 reaction product (trade name “TINUVIN 119”, manufactured by BASF), dibutylamine · 1,3-triazine · N, N′-bis (2,2,6,6-tetramethyl-4) -Polycondensate of piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine (trade name "TINUVIN 2020", manufactured by BASF), poly [ポ リ6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazin-2-diyl {2,2,6,6-tetramethyl-4-piperidyl} imino] hexa Methylene {(2,2,6,6-tetramethyl-4-piperidyl) imino} (trade name “TINUVIN 944”, manufactured by BASF), bis (1,2,2,6,6-pentamethyl-4-piperidyl) ) Mixture of sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (trade name “TINUVIN 765”, manufactured by BASF), bis (2,2,6,6) Tetramethyl-4-piperidyl) sebacate (trade name “TINUVIN 770”, manufactured by BASF), bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) decane diester, Reaction product of 1,1-dimethylethyl hydroperoxide and octane (trade name "TINUVIN 123", manufactured by BASF), bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5 -Bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate (trade name “TINUVIN 144”, manufactured by BASF), cyclohexane and N-butyl peroxide 2,2,6,6-tetra Reaction product of methyl-4-piperidinamine-2,4,6-trichloro-1,3,5-triazine with 2-aminoethanol (Trade name “TINUVIN 152”, manufactured by BASF), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6 -Pentamethyl-4-piperidyl sebacate mixture (trade name “TINUVIN 292”, manufactured by BASF), 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4- Mixed esterified product of piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (trade name “ADK STAB LA-63P And ADEKA Corporation). As the amine-based stabilizer, a hindered amine-based stabilizer is particularly preferable.

  When the pressure-sensitive adhesive layer of the present invention contains a light stabilizer, the content of the light stabilizer in the pressure-sensitive adhesive layer of the present invention (particularly, an acrylic pressure-sensitive adhesive layer) is not particularly limited, but the light-resistant agent has a light resistance. From the viewpoint of easy expression, the amount is preferably at least 0.1 part by weight, more preferably at least 0.2 part by weight, based on 100 parts by weight of the base polymer. In addition, the upper limit of the content is 5 parts by weight or less based on 100 parts by weight of the base polymer from the viewpoint that coloring by the light stabilizer itself hardly occurs and high transparency is easily obtained and optical characteristics. And more preferably 3 parts by weight or less.

  Although the formation of the pressure-sensitive adhesive layer of the present invention is not particularly limited, a crosslinking agent may be used. For example, the acrylic polymer in the acrylic pressure-sensitive adhesive layer can be crosslinked to control the gel fraction. In addition, the crosslinking agent can be used alone or in combination of two or more.

  The crosslinking agent is not particularly limited, but includes, for example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, and a metal chelate crosslinking agent. Agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, and the like. Among them, an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent are preferred, and an isocyanate-based crosslinking agent is more preferred.

  Examples of the isocyanate crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate Cycloaliphatic polyisocyanates such as cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate And aromatic polyisocyanates such as xylylene diisocyanate. Examples of the isocyanate-based crosslinking agent include trimethylolpropane / tolylene diisocyanate adduct (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) and trimethylolpropane / hexamethylene diisocyanate adduct (trade name) Commercial products such as "Coronate HL", manufactured by Nippon Polyurethane Industry Co., Ltd., and adduct of trimethylolpropane / xylylene diisocyanate (trade name "Takenate D-110N", manufactured by Mitsui Chemicals, Inc.) are also included.

  Examples of the epoxy crosslinking agent (polyfunctional epoxy compound) include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether , Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trime Roll propane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, and intramolecular And epoxy resins having two or more epoxy groups. Examples of the epoxy-based cross-linking agent include commercially available products such as trade name “Tetrad C” (manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  When a cross-linking agent is used for forming the pressure-sensitive adhesive layer of the present invention, the amount of the cross-linking agent used is not particularly limited. However, from the viewpoint of obtaining sufficient adhesion reliability, 0.1 to 100 parts by weight of the base polymer is used. It is preferably at least 001 parts by weight, more preferably at least 0.01 parts by weight. The upper limit of the amount used is preferably 10 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of the base polymer, from the viewpoint of obtaining appropriate flexibility in the pressure-sensitive adhesive layer and improving the adhesive strength. Is 5 parts by weight or less.

  The pressure-sensitive adhesive layer of the present invention (especially, an acrylic pressure-sensitive adhesive layer) contains a silane coupling agent from the viewpoint of improving the adhesion reliability under humidified conditions, particularly from the viewpoint of improving the adhesion reliability to glass. You may. The silane coupling agents can be used alone or in combination of two or more. When the pressure-sensitive adhesive layer contains a silane coupling agent, the adhesiveness under humidified conditions, in particular, the adhesiveness to glass can be improved.

  The silane coupling agent is not particularly limited. For example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane Methoxysilane and the like can be mentioned. Further, examples of the silane coupling agent include commercial products such as “KBM-403” (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Among them, γ-glycidoxypropyltrimethoxysilane is preferable as the silane coupling agent.

  When the pressure-sensitive adhesive layer of the present invention contains a silane coupling agent, the content of the silane coupling agent in the pressure-sensitive adhesive layer of the present invention (particularly, acrylic pressure-sensitive adhesive layer) is not particularly limited, It is preferably at least 0.01 part by weight, more preferably at least 0.02 part by weight, based on 100 parts by weight of the base polymer. Further, the upper limit of the content of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.5 part by weight or less based on 100 parts by weight of the base polymer.

  The pressure-sensitive adhesive layer of the present invention may further comprise a crosslinking accelerator, a tackifier resin (rosin derivative, polyterpene resin, petroleum resin, oil-soluble phenol, etc.), an antioxidant, a filler, a coloring agent (pigment or the like), if necessary. An additive such as a dye, an antioxidant, a chain transfer agent, a plasticizer, a softener, a surfactant, and an antistatic agent may be contained as long as the effects of the present invention are not impaired. In addition, such additives can be used alone or in combination of two or more.

  When the pressure-sensitive adhesive layer of the present invention is formed from a solvent-type acrylic pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer of the present invention has a viewpoint of controlling the amount of the extracted acrylate ions to 5 μg / g or less per 1 g of the pressure-sensitive adhesive layer. Of the above, it is preferable to contain an acrylic polymer and an ultraviolet absorber, the acrylic polymer being at least 50% by weight based on the total weight of the pressure-sensitive adhesive layer of 100% by weight, and the ultraviolet absorber being 100 parts by weight of the acrylic polymer. More preferably, the content is 0.05 to 9 parts by weight (preferably 0.1 to 8 parts by weight). Furthermore, the pressure-sensitive adhesive layer of the present invention contains 50 to 90% by weight (preferably 55 to 85% by weight) of a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms. At least one monomer selected from the group consisting of a nitrogen atom-containing monomer and a hydroxyl group-containing monomer in an amount of 10 to 50% by weight (preferably 15 to 40% by weight), and an alicyclic structure-containing monomer having 6 to 10 carbon atoms. 50% by weight or more of an acrylic polymer composed of a monomer mixture containing 0 to 40% by weight (preferably 0 to 30% by weight) with respect to 100% by weight of the total weight of the pressure-sensitive adhesive layer; It is particularly preferred to contain 0.05 to 9 parts by weight (preferably 0.1 to 8 parts by weight) based on parts by weight.

  When the pressure-sensitive adhesive layer of the present invention is formed from an active energy ray-curable acrylic pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer of the present invention has the above extracted acrylate ion amount of 5 μg / g or less per 1 g of the pressure-sensitive adhesive layer. From the viewpoint of the above, among the above, 50 to 90% by weight (preferably 55 to 85% by weight) of a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms, nitrogen It may contain an acrylic polymer composed of a monomer mixture of 10 to 50% by weight (preferably 15 to 40% by weight) of at least one monomer selected from the group consisting of an atom-containing monomer and a hydroxyl group-containing monomer. Preferably, the alkyl (meth) acrylate having a linear or branched alkyl group having 4 to 18 carbon atoms is 50 to 90% by weight (preferably 55 to 8%). %), An acrylic polymer composed of a monomer mixture containing 10 to 50% by weight (preferably 15 to 40% by weight) of at least one monomer selected from the group consisting of a nitrogen atom-containing monomer and a hydroxyl group-containing monomer. Is more preferably contained in an amount of 50% by weight or more. Furthermore, the pressure-sensitive adhesive layer of the present invention contains 50 to 90% by weight (preferably 55 to 85% by weight) of a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms. A nitrogen atom-containing monomer in an amount of 3 to 30% by weight (preferably 5 to 25% by weight), a hydroxyl group-containing monomer in an amount of 0.8 to 25% by weight (preferably 1 to 15% by weight), and an oil having 6 to 10 carbon atoms. It contains a ring structure-containing monomer in an amount of 0 to 40% by weight (preferably 0 to 30% by weight), and the total ratio of the nitrogen atom-containing monomer and the hydroxyl group-containing monomer is 10 to 50% by weight (preferably 15 to 40% by weight). It is particularly preferable to contain 50% by weight or more of an acrylic polymer composed of a monomer mixture.

  The haze of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less, in view of appearance characteristics, transparency, and optical characteristics. . In addition, in this specification, haze can be measured according to JISK7136 using a haze meter, for example.

  The total light transmittance of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 85% or more, more preferably 90% or more, and still more preferably 92% from the viewpoint of appearance characteristics, transparency, and optical characteristics. That is all. In this specification, the total light transmittance can be measured, for example, using a haze meter according to JIS K7361-1. The total light transmittance is the transmittance of light (visible light) having a wavelength of 400 to 780 nm.

A ^* of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably -0.5 or more, more preferably -0.3 or more, from the viewpoint of obtaining excellent optical characteristics and excellent appearance characteristics. And more preferably -0.1 or more. Further, from the viewpoint of obtaining excellent optical characteristics and excellent appearance characteristics, it is preferably 0.5 or less, more preferably 0.3 or less, and further preferably 0.1 or less. In this specification, a ^* value, L ^* a ^* b ^* is a ^* values of the color system, conforming to JIS Z 8781-4 (2013 years), for example, simplified Spectrophotometer (product ("DOT-3C", manufactured by Murakami Color Research Laboratory).

B ^* of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 0.7 or less, more preferably 0.5 or less, and further preferably 0.4 or less. When b ^* is 0.7 or less, excellent optical properties and excellent appearance properties are obtained. An optical product using the optical pressure-sensitive adhesive sheet of the present invention (particularly, an optical product having a display panel such as an LCD) has an advantage of not impairing the brightness, color depth, and color of a screen. In the present specification, b ^* values, L ^* a ^* b ^* a b ^* value of the color system, conforming to JIS Z 8781-4 (2013 years), for example, simplified Spectrophotometer (product ("DOT-3C", manufactured by Murakami Color Research Laboratory).

  The thickness of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 12 μm or more, and more preferably 12 μm or more, from the viewpoint of securing sufficient adhesion reliability to the silver nanowire layer and the protective layer described below, while ensuring ultraviolet absorption. It is at least 15 μm, more preferably at least 20 μm, particularly preferably at least 70 μm. When the thickness is 12 μm or more, the amount of extracted acrylic acid ions tends to decrease, which is preferable. Further, the thickness is preferably 500 μm or less, preferably 300 μm or less, and more preferably 200 μm or less from the viewpoint of optical characteristics.

  The method for producing the pressure-sensitive adhesive layer of the present invention (especially, an acrylic pressure-sensitive adhesive layer) is not particularly limited. For example, the pressure-sensitive adhesive composition was obtained by applying (coating) the pressure-sensitive adhesive composition on a substrate or a release liner. Drying and curing the pressure-sensitive adhesive composition layer, or applying (coating) the pressure-sensitive adhesive composition on a substrate or a release liner, and irradiating the obtained pressure-sensitive adhesive composition layer with active energy rays to cure the pressure-sensitive adhesive composition layer It is mentioned. Moreover, you may heat-dry as needed.

  Examples of the active energy rays include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, electron beams, and ultraviolet rays, and ultraviolet rays are particularly preferable. The irradiation energy, irradiation time, irradiation method and the like of the active energy ray are not particularly limited.

  The pressure-sensitive adhesive composition can be prepared by a known or commonly used method. For example, a solvent-type acrylic pressure-sensitive adhesive composition can be produced by mixing an additive (for example, an ultraviolet absorber or the like) with a solution containing the acrylic polymer, if necessary. For example, the active energy ray-curable acrylic pressure-sensitive adhesive composition is mixed with the above-mentioned acrylic monomer or a partially polymerized product thereof, if necessary, by mixing an additive (for example, an ultraviolet absorber). Can be made.

  In addition, you may utilize a well-known coating method for application | coating (coating) of the said adhesive composition. For example, a coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, and a direct coater may be used.

  In particular, when the pressure-sensitive adhesive layer is formed from an active energy ray-curable pressure-sensitive adhesive composition, the active energy ray-curable pressure-sensitive adhesive composition preferably contains a photopolymerization initiator. In addition, when the active energy ray-curable pressure-sensitive adhesive composition contains an ultraviolet absorber, it is preferable to include at least a photopolymerization initiator having light absorption characteristics in a wide wavelength range as the photopolymerization initiator. For example, it is preferable to include at least a photopolymerization initiator having an absorption property even with visible light in addition to ultraviolet light. This is because there is a concern that curing by active energy rays may be inhibited by the action of an ultraviolet absorber, but when a photopolymerization initiator having light absorption characteristics in a wide wavelength range is included, a high photocurability in the pressure-sensitive adhesive composition is obtained. This is because it becomes easier to obtain.

(Base material)
When the optical pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, the substrate is not particularly limited. For example, various optical films such as a plastic film, an anti-reflection (AR) film, a polarizing plate, and a retardation plate Is mentioned. Examples of the material such as the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyimide, and the like. Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "ARTON" (cyclic olefin polymer, manufactured by JSR Corporation), trade name "ZEONOR" (cyclic olefin polymer, Nippon Zeon) And plastic materials such as cyclic olefin-based polymers (manufactured by Co., Ltd.). In addition, these plastic materials can be used alone or in combination of two or more. In addition, the above-mentioned “substrate” is a portion that is adhered to the adherend together with the adhesive layer when the adhesive sheet is adhered to the adherend (such as an optical member). The release liner that is released when the pressure-sensitive adhesive sheet is used (at the time of application) is not included in the “base material”.

  The substrate is preferably transparent. The total light transmittance in the visible light wavelength region of the substrate (according to JIS K7361-1) is not particularly limited, but is preferably 85% or more, more preferably 88% or more. Further, the haze (according to JIS K 7136) of the base material is not particularly limited, but is preferably 1.5% or less, more preferably 1.0% or less.

  The thickness of the substrate is not particularly limited, but is preferably, for example, 12 to 75 μm. In addition, the said base material may have any form of a single layer and a multiple layer. Further, the surface of the base material may be appropriately subjected to a known and commonly used surface treatment such as a physical treatment such as a corona discharge treatment and a plasma treatment, and a chemical treatment such as an undercoat treatment.

(Release liner)
The optical pressure-sensitive adhesive sheet of the present invention may be provided with a release liner (separator) on the surface (pressure-sensitive surface) of the pressure-sensitive adhesive layer until use. In addition, when the optical pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, each pressure-sensitive adhesive surface may be protected by two release liners, respectively, or by one release liner having both release surfaces. It may be protected in a form (wound body) wound in a roll shape. The release liner is used as a protective material for the pressure-sensitive adhesive layer, and is peeled off when attached to an adherend. When the optical pressure-sensitive adhesive sheet of the present invention is a substrate-less pressure-sensitive adhesive sheet, the release liner also serves as a support for the pressure-sensitive adhesive layer. Note that the release liner does not necessarily have to be provided.

  As the release liner, a conventional release paper or the like can be used, and is not particularly limited. For example, a substrate having a release treatment layer, a low-adhesion substrate made of a fluoropolymer or a low-adhesion substrate made of a nonpolar polymer And the like. Examples of the substrate having the release treatment layer include a plastic film or paper surface-treated with a release treatment agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide. Examples of the fluorine-based polymer in the low-adhesion substrate made of the above fluoropolymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chloro Fluoroethylene-vinylidene fluoride copolymer is exemplified. Examples of the nonpolar polymer include olefin resins (eg, polyethylene, polypropylene, etc.). The release liner can be formed by a known or commonly used method. Also, the thickness of the release liner is not particularly limited.

(Optical pressure-sensitive adhesive sheet of the present invention)
The thickness of the optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 12 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and particularly preferably 50 μm or more. Further, the thickness is preferably 500 μm or less, preferably 300 μm or less, and more preferably 200 μm or less from the viewpoint of optical characteristics. The thickness of the optical pressure-sensitive adhesive sheet of the invention does not include the thickness of the release liner.

  The optical pressure-sensitive adhesive sheet of the present invention is attached to an optical member having a silver nanowire layer with respect to the resistance immediately after being attached to an optical member having a silver nanowire layer (sometimes referred to as “resistance immediately after attachment”). Then, the ratio of the resistance value after irradiation with ultraviolet light for 100 hours (may be referred to as “resistance value after 100 hours of UV irradiation”) [(resistance value after 100 hours of UV irradiation) / (resistance immediately after application) Value)] (times) (sometimes referred to as “resistance increase rate”) is not particularly limited, but is preferably 3 times or less (eg, 0 to 3 times), and more preferably 2 times or less (eg, 0 times). To 2 times), more preferably 1.5 times or less (for example, 0 to 1.5 times).

The “resistivity after 100 hours of UV irradiation” refers to, for example, an optical pressure-sensitive adhesive sheet adhered to an optical member having a silver nanowire layer in an environment having a temperature of 45 ° C. and a humidity of 50% RH. Below, it can be obtained by measuring the resistance value of an object irradiated with ultraviolet light at an illuminance of 65 W / cm ² for 100 hours. The “resistivity immediately after application” and the “resistivity after 100 hours of UV irradiation” can be measured using a known or commonly used resistance value measuring instrument. For example, the trade name “EC-80” (Manufactured by Napson Corporation). Further, a known or commonly used ultraviolet irradiator can be used for the irradiation of the ultraviolet rays, and for example, a trade name “Super Xenon Weather Meter SX75” (manufactured by Suga Test Instruments Co., Ltd.) can be used. In the measurement of the resistivity, when the optical pressure-sensitive adhesive sheet is attached to an optical member having a silver nanowire layer, the optical pressure-sensitive adhesive sheet may have a silver nanowire layer that may be provided with a protective layer described below on the surface. It is preferable to affix it to.

  The haze of the optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less, from the viewpoint of appearance characteristics, transparency and optical characteristics. is there.

  The total light transmittance of the optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 85% or more, more preferably 90% or more, and still more preferably 92, from the viewpoint of appearance characteristics, transparency, and optical characteristics. % Or more.

A ^* in the optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably -0.5 or more, more preferably -0.3 or more, from the viewpoint of obtaining excellent optical properties and excellent appearance properties. And more preferably −0.1 or more. Further, from the viewpoint of obtaining excellent optical characteristics and excellent appearance characteristics, it is preferably 0.5 or less, more preferably 0.3 or less, and further preferably 0.1 or less.

B ^* in the optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 0.7 or less, more preferably 0.5 or less, from the viewpoint of obtaining excellent optical properties and excellent appearance properties. , More preferably 0.4 or less.

  The pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer of the optical pressure-sensitive adhesive sheet of the present invention on the pressure-sensitive adhesive layer side of the present invention is not particularly limited, but is 6 N / 20 mm or more from the viewpoint of adhesion reliability to the silver nanowire layer and the protective layer described below. It is more preferably 7 N / 20 mm or more, and still more preferably 10 N / 20 mm or more. The above adhesive force is a 180 ° peel adhesive force, which is measured by peeling off from an adherend under the conditions of a tensile speed of 300 mm / min and a tensile angle of 180 ° (degree) according to JIS Z 0237. Can be.

Conventional optical pressure-sensitive adhesive sheets reduce the amount of (meth) acrylic acid used as a monomer component for forming an acrylic polymer in the pressure-sensitive adhesive layer, so that acrylic acid ions and methacrylic acid ions extracted from the pressure-sensitive adhesive sheet are reduced. Was set to 20 ng / cm ² or less per unit area of the pressure-sensitive adhesive layer to improve the corrosion resistance to the metal thin film to be attached. Such a conventional optical pressure-sensitive adhesive sheet has a content of acrylate ion and methacrylate ion of 20 ng / cm ² or less unless (meth) acrylic acid is used as a monomer component forming a polymer in the pressure-sensitive adhesive layer. It was possible to do. However, such a conventional optical pressure-sensitive adhesive sheet has sufficient corrosion resistance to the ITO layer, but sometimes has insufficient corrosion resistance to the silver nanowire layer. That is, even when (meth) acrylic acid was not used as a monomer component forming a polymer in the pressure-sensitive adhesive layer, the corrosion resistance of the pressure-sensitive adhesive sheet to the silver nanowire layer was sometimes insufficient. On the other hand, the optical pressure-sensitive adhesive sheet of the present invention is an optical pressure-sensitive adhesive sheet for a silver nanowire layer, and is extracted from the pressure-sensitive adhesive layer with pure water at 100 ° C. for 45 minutes, as measured by ion chromatography. The pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer in which the amount of the acrylic acid ions is 5 μg / g or less per 1 g of the pressure-sensitive adhesive layer, whereby the pressure-sensitive adhesive layer becomes the optical member side where the silver nanowire layer is present. Even when the optical pressure-sensitive adhesive sheet of the present invention is adhered (particularly, directly to the silver nanowire layer or to the layer that protects the silver nanowire layer), the silver nanowire by the acrylate ion can be used. By suppressing the ionization of silver in the wire layer, corrosion resistance (particularly, UV resistance) is improved, and a rise in resistance value (particularly, a rise in resistance value when irradiated with ultraviolet rays) can be suppressed. .

  The optical pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably produced according to a known or commonly used production method. For example, when the optical pressure-sensitive adhesive sheet of the present invention is a substrate-less pressure-sensitive adhesive sheet, it can be obtained by forming the pressure-sensitive adhesive layer of the present invention on a release liner by the above method. When the optical pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, the pressure-sensitive adhesive layer of the present invention may be obtained by directly forming the pressure-sensitive adhesive layer on the surface of the substrate (direct printing method), or once peeled. After forming the pressure-sensitive adhesive layer of the present invention on a liner, it may be obtained by providing (transferring) the pressure-sensitive adhesive layer of the present invention on a base material by transferring (laminating) the base material.

  The optical pressure-sensitive adhesive sheet of the present invention is used for optical applications. More specifically, it is used for application (optical use for a silver nanowire layer) to be applied to a product (optical product) using an optical member having a silver nanowire layer. When the optical pressure-sensitive adhesive sheet of the present invention is bonded to an optical member having a silver nanowire layer, the optical pressure-sensitive adhesive sheet is bonded (directly bonded) so that the adhesive surface of the pressure-sensitive adhesive layer of the present invention is in contact with the silver nanowire layer. It may be attached to a layer other than the silver nanowire layer (for example, a protective layer, an optical member described below other than the silver nanowire layer). The optical pressure-sensitive adhesive sheet of the present invention may be used, for example, for application (for attaching a silver nanowire layer) directly to a silver nanowire layer or to a layer for protecting the silver nanowire layer (a protective layer described later). preferable. Examples of the silver nanowire layer include a layer on which silver-containing metal fine wires are mesh-printed, a film (silver nanowire film) formed of silver-containing metal fine wires (nanowires), and the like.

  The optical member refers to a member having optical characteristics (for example, polarization, light refraction, light scattering, light reflection, light transmission, light absorption, light diffraction, optical rotation, visibility, and the like). Say. The substrate that constitutes the optical member is not particularly limited, and examples thereof include a substrate that constitutes a device (optical device) such as a display device (image display device) or an input device, or a substrate that is used for these devices. For example, a hard coat treatment is performed on at least one side of a plastic film such as a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, and a hard coat film (PET film or the like). Film, transparent conductive film, design film, decorative film, surface protection plate, prism, lens, color filter, transparent substrate (glass sensor, glass display panel (LCD etc.), glass substrate such as glass plate with transparent electrode, etc.) ) Or a substrate on which they are laminated (collectively, "functional film") Sometimes referred there), and the like. Further, these films may have a printing layer, a conductive polymer layer, and the like. Note that the above “plate” and “film” include forms such as a plate, a film, and a sheet, respectively. For example, the “polarizing film” includes a “polarizing plate” and a “polarizing sheet”. .

  Examples of the optical member include a touch sensor and a film sensor. More specifically, a film having an ITO (indium tin oxide) layer on the surface; a film having a zinc oxide (ZnO) layer on the surface; a film obtained by applying a liquid containing metal nanoparticles on the surface; A film using metal nanoparticles such as a film obtained by mesh-printing the surface with a liquid containing particles; a film obtained by applying a dispersion liquid containing carbon nanotubes to the surface; A film using carbon nanotubes such as a film obtained by mesh printing: a film using graphene such as a film having a graphene layer on the surface; a film having a conductive polymer layer on the surface, a conductive polymer Conduction such as a film obtained by mesh printing with a liquid containing Transparent conductive film such as a film with sexual polymer. In addition, a film using a metal (particularly, copper) such as a film in which a mesh-like thin metal wire pattern is formed on the film, a film having a metal layer, and the like can be given. Furthermore, a silver nanowire film is mentioned. In addition, among the above optical members, those to which the optical pressure-sensitive adhesive sheet of the present invention is attached have a silver nanowire layer.

  Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. The input device includes a touch panel and the like.

  The substrate constituting the optical member is not particularly limited. For example, a substrate made of glass, acrylic resin, polycarbonate, polyethylene terephthalate, cycloolefin polymer, metal thin film or the like (for example, a sheet-like, film-like, or plate-like substrate) Etc.). As described above, the “optical member” in the present invention also includes a member (design film, decorative film, surface protection film, etc.) that plays a role of decoration and protection while maintaining the visibility of the display device and the input device. Shall be considered.

  In the above optical member, the silver nanowire layer may be protected by a protective layer. That is, in the optical member, the silver nanowire layer may be provided with a protective layer (a layer that protects the silver nanowire layer).

  The protective layer preferably contains a resin as an essential component. Examples of the resin include known or commonly used resins, and examples thereof include an acrylic resin; a polyester resin such as polyethylene terephthalate; an aromatic resin such as polystyrene, polyvinyl toluene, and polyvinyl xylene; a polyimide; a polyamide; Polyurethane-based resin; Epoxy-based resin; Polyolefin-based resin; Acrylonitrile-butadiene-styrene copolymer (ABS); Cellulose-based resin; Silicone-based resin; Polyvinyl chloride; Polyacetate; Polynorbornene; Is mentioned. The resin may be a resin having conductivity (conductive resin), for example, conductive resins such as poly (3,4-ethylenedioxythiophene) (PEDOT), polyaniline, polythiophene, and polydiacetylene. Can be Among them, acrylic resins are preferred. The ratio of the resin (especially, acrylic resin) in the protective layer is not particularly limited, but is preferably 50% by weight or more (for example, 50 to 100% by weight) based on the total weight (100% by weight) of the protective layer. It is preferably at least 70% by weight, more preferably at least 95% by weight.

  Examples of the acrylic resin include the acrylic polymers exemplified and described as the base polymer contained in the above-mentioned pressure-sensitive adhesive layer of the present invention. Above all, a curable resin composed of the above-mentioned polyfunctional monomer (preferably an ultraviolet curable resin) is preferable, and pentaerythritol triacrylate (PETA), neopentyl glycol diacrylate (NPGDA), dipentaerythritol hexaacrylate (DPHA) ), A curable resin (preferably an ultraviolet curable resin) composed of a polyfunctional acrylate such as dipentaerythritol pentaacrylate (DPPA) or trimethylolpropane triacrylate (TMPTA). When the acrylic resin contains the polyfunctional monomer as a monomer component constituting the resin, the proportion of the polyfunctional monomer in all the monomer components (100% by weight) constituting the acrylic resin is as follows: Although not particularly limited, it is preferably 50% by weight or more (for example, 50 to 100% by weight), more preferably 70% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more.

  In the polymerization of the above monomer components, a photopolymerization initiator (photoinitiator) may be used. Examples of the photopolymerization initiator include the above-described photopolymerization initiators. When using a photopolymerization initiator, the amount of the photopolymerization initiator used is not particularly limited, for example, preferably 0.01 parts by weight or more, based on 100 parts by weight of all monomer components constituting the acrylic resin. , More preferably 0.1 part by weight or more, and 10 parts by weight or less, more preferably 7 parts by weight or less.

  For the formation of the protective layer, the above-mentioned crosslinking agent may be further used. The protective layer may further include a stabilizer, a corrosion inhibitor, an antioxidant, a filler, a coloring agent (such as a pigment or a dye), an antioxidant, a plasticizer, a softener, and a surfactant, if necessary. And an additive such as an antistatic agent.

  The protective layer may be provided so as to cover the silver nanowire layer (so that the silver nanowire layer is buried), or may be provided so that a part of the silver nanowire layer protrudes from the surface of the protective layer. May be.

  More specifically, an embodiment in which the optical pressure-sensitive adhesive sheet of the present invention is used for a silver nanowire layer in optical applications will be described. FIGS. 1 and 2 show an example of an embodiment in which the optical pressure-sensitive adhesive sheet of the present invention is used for a silver nanowire layer in optical applications (particularly, for attaching a silver nanowire layer). 1 and 2 also correspond to an embodiment used for a film sensor. The mode in which the optical pressure-sensitive adhesive sheet of the present invention is used for a silver nanowire layer in optical applications is not limited to the modes shown in FIGS. 1 and 2 are also schematic cross-sectional views showing an example of an optical product using the optical pressure-sensitive adhesive sheet of the present invention. 1 and 2 has a structure in which an optical member is bonded via an optical pressure-sensitive adhesive sheet of the present invention. 1 and 2, 1 is an optical product, 11 is a cover, 12 is an optical pressure-sensitive adhesive sheet of the present invention, 13 is a substrate, 14 is a silver nanowire layer, and 15 is It is a protective layer. The cover 11 is a cover glass or a cover lens. The substrate 13 is a substrate that supports the silver nanowire layer 14.

  In FIG. 1, an optical member having a silver nanowire layer is used as the optical member, and the optical adhesive sheet 12 of the present invention is laminated on one surface side of the silver nanowire layer 14 via a protective layer 15. ing. The protective layer 15 is provided so as to cover the silver nanowire layer 14 (so that the silver nanowire layer 14 is buried). Therefore, the optical pressure-sensitive adhesive sheet of the present invention is used for silver nanowire layer applications (particularly, silver nanowire layer application applications).

  In FIG. 2, as in FIG. 1, an optical member having a silver nanowire layer is used as the optical member. In the optical product 1 shown in FIG. 2, the optical pressure-sensitive adhesive sheet 12 of the present invention is used so as to be directly attached to the silver nanowire layer 14. The protective layer 15 is provided so that the silver nanowire layer 14 protrudes. Therefore, the optical pressure-sensitive adhesive sheet of the present invention is used for silver nanowire layer applications (particularly, silver nanowire layer application applications).

  In the optical product 1 of FIGS. 1 and 2, the optical pressure-sensitive adhesive sheet 12 of the present invention is attached to an optical member having a silver nanowire layer 14. Further, the optical pressure-sensitive adhesive sheet 12 of the present invention has excellent corrosion resistance to the silver nanowire layer. For this reason, in the optical product 1, the corrosion of the silver nanowire layer by the acrylate ion is effectively suppressed. Thus, in the optical product 1, since the optical pressure-sensitive adhesive sheet 12 of the present invention is used, corrosion of the silver nanowire layer is suppressed, and deterioration of the optical product 1 is also suppressed.

(Optical member with adhesive sheet for optics for silver nanowire layer)
The optical member with an optical pressure-sensitive adhesive sheet for a silver nanowire layer includes at least the above-described optical member and the optical pressure-sensitive adhesive sheet of the present invention.

  As the optical member with an optical pressure-sensitive adhesive sheet for the silver nanowire layer, for example, the substrate is an optical member provided with a silver nanowire layer, and the optical pressure-sensitive adhesive of the present invention in the form of a pressure-sensitive adhesive sheet with a substrate. Sheet. More specifically, a pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer of the present invention on at least one side of the silver nanowire layer via the protective layer and / or the sheet-shaped or film-shaped optical member, or a silver nanowire layer And a pressure-sensitive adhesive sheet with an optical member such as a pressure-sensitive adhesive sheet provided directly with the pressure-sensitive adhesive layer of the present invention on at least one side thereof.

  According to the pressure-sensitive adhesive sheet with an optical member, the optical member having the silver nanowire layer can be fixed or temporarily fixed to a desired position via the pressure-sensitive adhesive surface of the optical pressure-sensitive adhesive sheet of the present invention. In the optical pressure-sensitive adhesive sheet of the present invention, corrosion on the silver nanowire layer is effectively suppressed. Therefore, in the pressure-sensitive adhesive sheet with an optical member, deterioration due to corrosion of the silver nanowire layer hardly occurs.

(Optical products)
The optical product includes at least the optical member provided with the silver nanowire layer and the optical pressure-sensitive adhesive sheet of the present invention. Although it does not specifically limit as an optical product, For example, the optical product (optical product 1) shown in FIG. 1 or FIG. 2 etc. is mentioned. Since the optical product includes the optical pressure-sensitive adhesive sheet of the present invention having excellent corrosion resistance (particularly, UV resistance) to the silver nanowire layer, the optical product includes corrosion of the silver nanowire layer (particularly, irradiation of ultraviolet rays). (Corrosion of the silver nanowires due to corrosion).

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. All parts (parts by weight) indicate the number of parts of each component described. Examples 1 and 2 are described as reference examples.

(Preparation example 1 of acrylic polymer)
Dicyclopentanyl methacrylate (DCPMA, dicyclopentanyl methacrylate): 60 parts by weight, methyl methacrylate (MMA, methyl methacrylate): 40 parts by weight, α-thioglycerol as a chain transfer agent: 3.5 parts by weight, Then, 100 parts by weight of toluene as a polymerization solvent were charged into a four-necked flask, and these were stirred at 70 ° C. for 1 hour under a nitrogen atmosphere. Next, 0.2 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged into a four-necked flask and reacted at 70 ° C. for 2 hours, and subsequently at 80 ° C. for 2 hours. Reacted. Thereafter, the reaction solution is put into a temperature atmosphere of 130 ° C., and the toluene, the chain transfer agent, and the unreacted monomer are removed by drying, and the solid acrylic polymer (“sometimes referred to as acrylic polymer (A)”) ) Got. The weight average molecular weight of the acrylic polymer (A) was 5,100.

(Example 1)
A monomer mixture composed of 67 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 18 parts by weight of 2-hydroxyethyl acrylate (HEA) was added to a monomer mixture. After blending a polymerization initiator (trade name “Irgacure 651”, manufactured by BASF): 0.035 parts by weight, and a photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF): 0.035 parts by weight, Ultraviolet irradiation was performed until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s, to obtain a prepolymer composition in which a part of the monomer components was polymerized.
5 parts by weight of the acrylic polymer (A), 0.075 parts by weight of hexanediol diacrylate (HDDA), and a silane coupling agent (trade name “KBM-403”, Shin-Etsu Chemical Co., Ltd.) (Manufactured by K.K.): 0.3 part by weight was added and mixed to obtain an acrylic pressure-sensitive adhesive composition.
The acrylic pressure-sensitive adhesive composition was applied on a polyethylene terephthalate (PET) -based release liner (manufactured by Nitto Denko Corporation, thickness: 125 μm) to form a pressure-sensitive adhesive composition layer. Next, a PET-based release liner (manufactured by Nitto Denko Corporation, thickness: 125 μm) was provided on the pressure-sensitive adhesive composition layer to cover the pressure-sensitive adhesive composition layer and block oxygen. Then, a laminate (laminate (I)) having a configuration of [release liner / pressure-sensitive adhesive composition layer / release liner] was obtained.
Next, ultraviolet light having an illuminance of 3 mW / cm ² was irradiated on the laminate (I) from the upper surface (release liner side) of the laminate (I) with a black light (manufactured by Toshiba Corporation) for 300 seconds. did. Further, a drying treatment is performed for 2 minutes in a drier at 90 ° C. to evaporate the remaining monomer, and the double-sided adhesive having the configuration of [release liner / adhesive layer / release liner], the adhesive surfaces on both sides being protected by a release liner. A sheet (substrate-less pressure-sensitive adhesive sheet) was produced. The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Example 2)
A double-sided pressure-sensitive adhesive sheet (substrate-less pressure-sensitive adhesive sheet) was produced in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Example 3)
2-ethylhexyl acrylate (2EHA): 40.5 parts by weight, isostearyl acrylate (ISTA): 40.5 parts by weight, N-vinyl-2-pyrrolidone (NVP): 18 parts by weight, 4-hydroxybutyl acrylate ( 4HBA): A monomer mixture composed of 1 part by weight, a photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF): 0.05 parts by weight, and a photopolymerization initiator (trade name “Irgacure 184”) After mixing 0.5 part by weight of a monomer component, the monomer component was irradiated with ultraviolet rays until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s. A partially polymerized prepolymer composition was obtained.
To the above prepolymer composition, trimethylolpropane triacrylate (TMPTA): 0.02 part by weight, and a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.3 part by weight Was added and mixed to obtain an acrylic pressure-sensitive adhesive composition.
Using the acrylic pressure-sensitive adhesive composition, a double-sided pressure-sensitive adhesive sheet having a configuration of [release liner / pressure-sensitive adhesive layer / release liner] in which the pressure-sensitive adhesive surfaces on both sides are protected by a release liner in the same manner as in Example 1 ( Base material-less pressure-sensitive adhesive sheet). The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Example 4)
A double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) was produced in the same manner as in Example 3, except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Example 5)
2-ethylhexyl acrylate (2EHA): 40.5 parts by weight, isostearyl acrylate (ISTA): 40.5 parts by weight, N-vinyl-2-pyrrolidone (NVP): 18 parts by weight, 4-hydroxybutyl acrylate ( 4HBA): A monomer mixture composed of 1 part by weight, a photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF): 0.05 parts by weight, and a photopolymerization initiator (trade name “Irgacure 184”) After mixing 0.5 part by weight of a monomer component, the monomer component was irradiated with ultraviolet rays until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s. A partially polymerized prepolymer composition was obtained.
To the above prepolymer composition, trimethylolpropane triacrylate (TMPTA): 0.15 parts by weight, a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.3 parts by weight, And 0.15 parts by weight of α-thioglycerol as a chain transfer agent were added and mixed to obtain an acrylic pressure-sensitive adhesive composition.
Using the acrylic pressure-sensitive adhesive composition, a double-sided pressure-sensitive adhesive sheet having a configuration of [release liner / pressure-sensitive adhesive layer / release liner] in which the pressure-sensitive adhesive surfaces on both sides are protected by a release liner in the same manner as in Example 1 ( Base material-less pressure-sensitive adhesive sheet). The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Example 6)
A double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) was produced in the same manner as in Example 5, except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Example 7)
2-ethylhexyl acrylate (2EHA): 28.5 parts by weight, isostearyl acrylate (ISTA): 28.5 parts by weight, isobornyl acrylate (IBXA): 22 parts by weight, 4-hydroxybutyl acrylate (4HBA): To a monomer mixture composed of 21 parts by weight, 0.05 parts by weight of a photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF) and a photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF) ): After blending 0.5 part by weight, irradiate ultraviolet rays until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) becomes about 20 Pa · s, and a part of the monomer components A polymerized prepolymer composition was obtained.
0.3 parts by weight of 1,6-hexanediol diacrylate (trade name “NK Ester A-HD-N”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 0.3 parts by weight, a silane coupling agent (product) Name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.3 part by weight, photopolymerization initiator (trade name “Irgacure 651”, manufactured by BASF): 0.05 part by weight, and photopolymerization initiator (Trade name "Irgacure 819", manufactured by BASF): 0.5 part by weight was added and mixed to obtain an acrylic pressure-sensitive adhesive composition.
Using the acrylic pressure-sensitive adhesive composition, a double-sided pressure-sensitive adhesive sheet having a configuration of [release liner / pressure-sensitive adhesive layer / release liner] in which the pressure-sensitive adhesive surfaces on both sides are protected by a release liner in the same manner as in Example 1 ( Base material-less pressure-sensitive adhesive sheet). The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Example 8)
A double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) was produced in the same manner as in Example 7, except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Example 9)
As monomer components, 2-ethylhexyl acrylate (2EHA): 63 parts by weight, methyl methacrylate (MMA): 9 parts by weight, N-vinyl-2-pyrrolidone (NVP): 15 parts by weight, 2-hydroxyethyl acrylate ( HEA): 13 parts by weight, and 175 parts by weight of ethyl acetate as a polymerization solvent were charged into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this manner, 0.2 parts by weight of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the temperature was raised to 63 ° C. and reacted for 10 hours. . Thereafter, ethyl acetate was added to obtain an acrylic polymer solution having a solid content of 36% by weight. The weight average molecular weight of the acrylic polymer in the acrylic polymer solution was 850,000.
1.1 parts by weight of an isocyanate-based crosslinking agent (trade name “Takenate D-110N”, manufactured by Mitsui Chemicals, Inc.): 1.1 parts by weight, a silane coupling agent (trade name “KBM-403”, Shin-Etsu Chemical) Industrial Co., Ltd.): 0.15 parts by weight, and 1.5 parts by weight of an ultraviolet absorbent (trade name "TINUVIN 384-2", manufactured by BASF): 1.5 parts by weight, and mixed to obtain an acrylic pressure-sensitive adhesive composition. Obtained.
The acrylic pressure-sensitive adhesive composition was applied on a polyethylene terephthalate (PET) -based release liner (manufactured by Nitto Denko Corporation, thickness: 125 μm) to obtain a pressure-sensitive adhesive composition layer. Next, heating and drying were performed at 130 ° C. for 3 minutes to form an adhesive layer. Then, aging is performed at 23 ° C. for 120 hours to prepare a double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) having a configuration of “release liner / pressure-sensitive adhesive layer / release liner”, with the pressure-sensitive adhesive surfaces on both sides protected by a release liner. did. The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Example 10)
A double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) was produced in the same manner as in Example 9 except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Example 11)
As monomer components, 2-ethylhexyl acrylate (2EHA): 63 parts by weight, methyl methacrylate (MMA): 9 parts by weight, N-vinyl-2-pyrrolidone (NVP): 15 parts by weight, 2-hydroxyethyl acrylate ( HEA): 13 parts by weight, and 175 parts by weight of ethyl acetate as a polymerization solvent were charged into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen in the polymerization system in this manner, 0.2 parts by weight of 2,2′-azobisisobutyronitrile was added as a polymerization initiator, and the temperature was raised to 63 ° C. and reacted for 10 hours. . Thereafter, ethyl acetate was added to obtain an acrylic polymer solution having a solid content of 36% by weight. The weight average molecular weight of the acrylic polymer in the acrylic polymer solution was 850,000.
1.1 parts by weight of an isocyanate-based crosslinking agent (trade name “Takenate D-110N”, manufactured by Mitsui Chemicals, Inc.): 1.1 parts by weight, a silane coupling agent (trade name “KBM-403”, Shin-Etsu Chemical) Industrial Co., Ltd.): 0.15 parts by weight, and an ultraviolet absorber (trade name "KEMISORB 111", manufactured by Chemipro Kasei Co., Ltd.): 1 part by weight, and mixed to obtain an acrylic pressure-sensitive adhesive composition. Was.
Using the acrylic pressure-sensitive adhesive composition, a double-sided pressure-sensitive adhesive sheet having a configuration of [release liner / pressure-sensitive adhesive layer / release liner] in which the pressure-sensitive adhesive surfaces on both sides are protected by a release liner in the same manner as in Example 9 ( Base material-less pressure-sensitive adhesive sheet). The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Comparative Example 1)
N-butyl acrylate (BA): 67 parts by weight, cyclohexyl acrylate (CHA): 17 parts by weight, 2-hydroxyethyl acrylate (HEA): 8 parts by weight, 4-hydroxybutyl acrylate (4HBA): 27 parts by weight Of a photopolymerization initiator (trade name "Irgacure 651", manufactured by BASF): 0.05 parts by weight and a photopolymerization initiator (trade name "Irgacure 184", manufactured by BASF): 0 After mixing 0.05 parts by weight, ultraviolet light was applied until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s, and the prepolymerized part of the monomer component A polymer composition was obtained.
0.1 parts by weight of dipentaerythritol hexaacrylate (DPHA) and 0.3 parts by weight of a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) in the above prepolymer composition Was added and mixed to obtain an acrylic pressure-sensitive adhesive composition.
Using the acrylic pressure-sensitive adhesive composition, a double-sided pressure-sensitive adhesive sheet having a configuration of [release liner / pressure-sensitive adhesive layer / release liner] in which the pressure-sensitive adhesive surfaces on both sides are protected by a release liner in the same manner as in Example 1 ( Base material-less pressure-sensitive adhesive sheet). The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 50 μm.

(Comparative Example 2)
A double-sided pressure-sensitive adhesive sheet (base-less pressure-sensitive adhesive sheet) was produced in the same manner as in Comparative Example 1, except that the thickness of the pressure-sensitive adhesive layer was 100 μm. The thickness of the double-sided pressure-sensitive adhesive sheet (excluding the release liner) was 100 μm.

(Evaluation)
The following evaluations were performed on the double-sided PSA sheets obtained in Examples and Comparative Examples. The results are shown in Table 1.

(1) Amount of extracted acrylic acid ions (preparation of test pieces)
From the double-sided pressure-sensitive adhesive sheets obtained in the examples and comparative examples, sheet pieces having a size of 10 cm in width and 10 cm in length were cut out. The release liner was peeled off, and a PET film (“Lumirror S10” manufactured by Toray Industries, Inc., thickness 25 μm) was stuck on one of the adhesive surfaces to prepare a test piece with only one of the adhesive surfaces exposed. The mass of the pressure-sensitive adhesive layer in the test piece was 0.5 g when the thickness of the pressure-sensitive adhesive layer was 50 μm, and 1 g when it was 100 μm. In addition, the PET film used was subjected to warm extraction (120 ° C. × 1 hour) and further washed with pure water. In addition, in this specification, "heating extraction" means that what was put in pure water was heated to a predetermined temperature and left for a predetermined time to extract an arbitrary component. For example, “heating extraction (120 ° C. × 1 hour)” indicates that a component placed in pure water is left at a temperature of 120 ° C. for 1 hour to extract an arbitrary component.

(Heating extraction of acrylate ion)
Next, the test piece was placed in pure water (50 ml) and subjected to warm extraction (100 ° C. × 45 minutes) with a dryer to obtain an extract.
Next, the amount (unit: μg) of acrylate ions in the extract obtained above was measured by ion chromatography (ion chromatography), and the amount of acrylate ions per 1 g of the pressure-sensitive adhesive layer in the test piece was measured. (Amount of extracted acrylic acid ions) (unit: μg / g) was calculated, and the results are shown in Table 1.
[Measurement conditions for ion chromatography]
Analyzer: Thermo Fisher Scientific, ICS-3000
Separation column: Ion Pac AS18 (4 mm x 250 mm)
Guard column: Ion Pac AG18 (4 mm x 50 mm)
Removal system: AERS-500 (External mode)
Detector: Electric conductivity detector Eluent: KOH aqueous solution
(Using eluent generator EGIII)
Eluent flow rate: 1.0 ml / min Sample injection volume: 250 μl

(2) UV resistance (Synthesis of silver nanowires and preparation of silver nanowire dispersion)
At 160 ° C., 5 ml of anhydrous ethylene glycol and 0.5 ml of a solution of PtCl ₂ in anhydrous ethylene glycol (concentration: 1.5 × 10 ⁻⁴ mol / l) were added to a reaction vessel equipped with a stirrer. After a lapse of 4 minutes, the obtained solution was added with 2.5 ml of an anhydrous ethylene glycol solution of AgNO ₃ (concentration: 0.12 mol / l) and an anhydrous ethylene glycol solution of polyvinylpyrrolidone (Mw: 55000) (concentration: 0. 36 mol / l): 5 ml simultaneously and dropwise over 6 minutes. After this dropping, the mixture was heated to 160 ° C. and reacted for 1 hour or more until AgNO ₃ was completely reduced, thereby producing a coarse silver nanowire. Next, acetone is added to the reaction mixture containing the coarse silver nanowires obtained as described above until the volume of the reaction mixture becomes 5 times, and then the reaction mixture is centrifuged (2000 rpm, 20 minutes). ) To obtain silver nanowires.
The obtained silver nanowire had a minor axis of 30 nm to 40 nm, a major axis of 30 nm to 50 nm, and a length of 30 μm to 50 μm.
In pure water, 0.2 parts by weight of the silver nanowires and 0.1 part by weight of pentaethylene glycol dodecyl ether were dispersed in 100 parts by weight of water to prepare a silver nanowire dispersion.

(Preparation of composition for forming protective layer)
A mixture of isopropyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) and diacetone alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) at a weight ratio of 1: 1 was used as a solvent. Dipentaerythritol hexaacrylate (DPHA) (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “A-DPH”): 3.0 parts by weight, based on 100 parts by weight of the solvent, and photopolymerization started An agent (trade name "Irgacure 907", manufactured by BASF): 0.09 parts by weight was added to prepare a composition for forming a protective layer.

(Preparation of transparent conductive film (1))
As a transparent substrate, a norbornene-cyclohexane type cyclic olefin-based film (trade name “ZEONOR”, manufactured by Zeon Corporation, in-plane retardation Re: 1.7 nm, thickness-direction retardation Rth: 1.8 nm) was used. .
Using a bar coater (trade name “Bar Coater No. 20”, manufactured by Dai-ichi Rika Co., Ltd.), the silver nanowire dispersion was applied on the entire surface of the transparent substrate, and dried in a blow dryer at 120 ° C. After drying for 2 minutes, a silver nanowire layer was formed. Thereafter, the composition for forming a protective layer was applied to the entire surface of the silver nanowire layer by a slot die with a wet film thickness of 4 μm, and dried in a blow dryer at 120 ° C. for 2 minutes. Next, the composition for forming a protective layer is cured by irradiating ultraviolet light having an integrated illuminance of 400 mJ / cm ² with an ultraviolet irradiation apparatus (manufactured by Fusion UV Systems) having an oxygen concentration of 100 ppm to form a protective layer, thereby forming a transparent conductive layer. Film (1) [transparent substrate / transparent conductive layer (including silver nanowire layer and protective layer)] was obtained.
The transparent conductive film (1) had a surface resistance of 50 Ω / □, a total light transmittance of 91.4%, and a haze of 2.0%.

(Measurement of resistance value)
The release liner was peeled off from the double-sided pressure-sensitive adhesive sheet obtained in each of Examples and Comparative Examples, and the transparent conductive layer surface (the silver nanowire layer forming surface side) of the transparent conductive film (1) was bonded onto one of the adhesive surfaces. A glass plate (trade name “MICRO SLIDE GLASS S200200”, manufactured by Matsunami Glass Co., Ltd., size: 50 mm × 45 mm, thickness: 1.2 to 1.5 mm) is laminated on the other adhesive surface. I got Next, the transparent conductive film (1) and the double-sided pressure-sensitive adhesive sheet in the portion of the laminate protruding from the size of the glass plate were cut off to obtain a test piece (size: 50 mm × 45 mm) as shown in FIGS. Was.
The resistance value of the test piece was 50Ω / □, which was referred to as “resistance value immediately after application”. Next, using a Super Xenon Weather Meter SX75 (manufactured by Suga Test Instruments Co., Ltd.), the above test piece was tested under the conditions of temperature: 45 ° C., humidity: 50% RH and illuminance: 65 W / m ^2. The plate was left for 100 hours in a state where the plate was irradiated with ultraviolet rays. The resistance value of the test piece after standing for 100 hours was measured and defined as "resistance value after 100 hours of UV irradiation". Then, the ratio of the “resistance value after 100 hours of UV irradiation” to the “resistance value immediately after pasting” [(resistance value after 100 hours of UV irradiation) / (resistance value immediately after pasting)] was measured. Table 1 shows the resistance value increase rate (times). The lower the rate of increase in the resistance value, the better the UV resistance. The “resistance immediately after application” and the “resistance after 100 hours of UV irradiation” were measured using “EC-80” manufactured by Napson Corporation.

REFERENCE SIGNS LIST 1 optical product 11 cover 12 optical adhesive sheet 13 of the present invention base material 14 silver nanowire layer 15 protective layer 30 test piece 31 transparent conductive film (1)
32 Transparent substrate 33 Silver nanowire layer 34 Protective layer 35 Double-sided adhesive sheet 36 Glass plate

Claims (13)

An adhesive sheet having an adhesive layer,
The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer as a base polymer,
The acrylic polymer contains, as constituent units, (i) a hydroxyl group-containing monomer and / or a nitrogen atom-containing monomer, and (ii) isostearyl (meth) acrylate and / or methyl methacrylate,
The amount of acrylate ions extracted from the pressure-sensitive adhesive layer with pure water at 100 ° C. for 45 minutes, measured by ion chromatography, is 5 μg / g or less per 1 g of the pressure-sensitive adhesive layer. Pressure sensitive adhesive sheet for silver nanowire layer. The optical pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic polymer includes, as constituent units, two or more alkyl (meth) acrylates having a linear or branched alkyl group having 1 to 20 carbon atoms. . The optical pressure-sensitive adhesive sheet according to claim 2, wherein the (meth) acrylic acid alkyl ester contains 2-ethylhexyl acrylate. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein a ratio of the carboxyl group-containing monomer in all monomer components constituting the acrylic polymer is 0.05% by weight or less. The ratio of the alkyl (meth) acrylate having a linear or branched alkyl group having 4 to 18 carbon atoms in all monomer components constituting the acrylic polymer is 50 to 90% by weight. The pressure-sensitive adhesive sheet for optical use according to any one of Items 1 to 4. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the content of the acrylic polymer in the pressure-sensitive adhesive layer is 90% by weight or more based on the total weight of the pressure-sensitive adhesive layer. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the acrylic polymer includes an N-vinyl cyclic amide as a constituent unit. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive layer contains an ultraviolet absorber. The optical pressure-sensitive adhesive sheet according to claim 8 , wherein the ultraviolet absorber has an absorbance A determined below of 0.5 or less.
Absorbance A: Absorbance measured by exposing a 0.08% toluene solution of the ultraviolet absorber to light having a wavelength of 400 nm. 10. The ultraviolet absorber according to claim 8 , wherein the ultraviolet absorber is at least one ultraviolet absorber selected from the group consisting of a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a hydroxyphenyltriazine-based ultraviolet absorber. Optical adhesive sheet. The optical material according to any one of claims 8 to 10, wherein the pressure-sensitive adhesive layer contains the ultraviolet absorber in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the base polymer in the pressure-sensitive adhesive layer. Adhesive sheet. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 11, which is used for directly attaching to a silver nanowire layer or attaching to a layer for protecting the silver nanowire layer. The optical pressure-sensitive adhesive sheet according to any one of claims 1 to 12 , which is used for a film sensor.

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